Remove polylith/API mode (#2967)

This removes most of the code used for polylith/API mode.

This removes the `/api` internal endpoints entirely. 

Binary size change roughly 5%: 
```
51437560 Feb 13 10:15 dendrite-monolith-server # old
48759008 Feb 13 10:15 dendrite-monolith-server # new
```

4 files changed, 26 insertions, 169 deletions

diff --git a/.github/ISSUE_TEMPLATE/BUG_REPORT.md b/.github/ISSUE_TEMPLATE/BUG_REPORT.md
index f40c5660..a3b8c075 100644
--- a/.github/ISSUE_TEMPLATE/BUG_REPORT.md
+++ b/.github/ISSUE_TEMPLATE/BUG_REPORT.md
@@ -17,7 +17,6 @@ see: https://www.matrix.org/security-disclosure-policy/
 ### Background information
 <!-- Please include versions of all software when known e.g database versions, docker versions, client versions -->
 - **Dendrite version or git SHA**:
-- **Monolith or Polylith?**:
 - **SQLite3 or Postgres?**:
 - **Running in Docker?**:
 - **`go version`**:
diff --git a/.github/workflows/dendrite.yml b/.github/workflows/dendrite.yml
index e35ad2ae..2f615a6a 100644
--- a/.github/workflows/dendrite.yml
+++ b/.github/workflows/dendrite.yml
@@ -25,7 +25,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18
+          go-version: "stable"
           cache: true
 
       - name: Install Node
@@ -62,14 +62,14 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18
+          go-version: "stable"
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3
 
   # run go test with different go versions
   test:
     timeout-minutes: 10
-    name: Unit tests (Go ${{ matrix.go }})
+    name: Unit tests
     runs-on: ubuntu-latest
     # Service containers to run with `container-job`
     services:
@@ -91,25 +91,21 @@ jobs:
           --health-interval 10s
           --health-timeout 5s
           --health-retries 5
-    strategy:
-      fail-fast: false
-      matrix:
-        go: ["1.19"]
     steps:
       - uses: actions/checkout@v3
       - name: Setup go
         uses: actions/setup-go@v3
         with:
-          go-version: ${{ matrix.go }}
+          go-version: "stable"
       - uses: actions/cache@v3
         # manually set up caches, as they otherwise clash with different steps using setup-go with cache=true
         with:
           path: |
             ~/.cache/go-build
             ~/go/pkg/mod
-          key: ${{ runner.os }}-go${{ matrix.go }}-unit-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-stable-unit-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            ${{ runner.os }}-go${{ matrix.go }}-unit-
+            ${{ runner.os }}-go-stable-unit-
       - name: Set up gotestfmt
         uses: gotesttools/gotestfmt-action@v2
         with:
@@ -130,7 +126,6 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go: ["1.18", "1.19", "1.20.0"]
         goos: ["linux"]
         goarch: ["amd64", "386"]
     steps:
@@ -138,15 +133,15 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v3
         with:
-          go-version: ${{ matrix.go }}
+          go-version: "stable"
       - uses: actions/cache@v3
         with:
           path: |
             ~/.cache/go-build
             ~/go/pkg/mod
-          key: ${{ runner.os }}-go${{ matrix.go }}${{ matrix.goos }}-${{ matrix.goarch }}-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-stable-${{ matrix.goos }}-${{ matrix.goarch }}-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            key: ${{ runner.os }}-go${{ matrix.go }}${{ matrix.goos }}-${{ matrix.goarch }}-
+            key: ${{ runner.os }}-go-stable-${{ matrix.goos }}-${{ matrix.goarch }}-
       - name: Install dependencies x86
         if: ${{ matrix.goarch == '386' }}
         run: sudo apt update && sudo apt-get install -y gcc-multilib
@@ -164,23 +159,22 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: ["1.18", "1.19", "1.20.0"]
         goos: ["windows"]
         goarch: ["amd64"]
     steps:
       - uses: actions/checkout@v3
-      - name: Setup Go ${{ matrix.go }}
+      - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: ${{ matrix.go }}
+          go-version: "stable"
       - uses: actions/cache@v3
         with:
           path: |
             ~/.cache/go-build
             ~/go/pkg/mod
-          key: ${{ runner.os }}-go${{ matrix.go }}${{ matrix.goos }}-${{ matrix.goarch }}-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-stable-${{ matrix.goos }}-${{ matrix.goarch }}-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            key: ${{ runner.os }}-go${{ matrix.go }}${{ matrix.goos }}-${{ matrix.goarch }}-
+            key: ${{ runner.os }}-go-stable-${{ matrix.goos }}-${{ matrix.goarch }}-
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y gcc-mingw-w64-x86-64 # install required gcc
       - env:
@@ -206,7 +200,7 @@ jobs:
   integration:
     timeout-minutes: 20
     needs: initial-tests-done
-    name: Integration tests (Go ${{ matrix.go }})
+    name: Integration tests
     runs-on: ubuntu-latest
     # Service containers to run with `container-job`
     services:
@@ -228,16 +222,12 @@ jobs:
           --health-interval 10s
           --health-timeout 5s
           --health-retries 5
-    strategy:
-      fail-fast: false
-      matrix:
-        go: ["1.19"]
     steps:
       - uses: actions/checkout@v3
       - name: Setup go
         uses: actions/setup-go@v3
         with:
-          go-version: ${{ matrix.go }}
+          go-version: "stable"
       - name: Set up gotestfmt
         uses: gotesttools/gotestfmt-action@v2
         with:
@@ -248,9 +238,9 @@ jobs:
           path: |
             ~/.cache/go-build
             ~/go/pkg/mod
-          key: ${{ runner.os }}-go${{ matrix.go }}-test-race-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go-stable-test-race-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            ${{ runner.os }}-go${{ matrix.go }}-test-race-
+            ${{ runner.os }}-go-stable-test-race-
       - run: go test -race -json -v -coverpkg=./... -coverprofile=cover.out $(go list ./... | grep -v /cmd/dendrite*) 2>&1 | gotestfmt
         env:
           POSTGRES_HOST: localhost
@@ -261,6 +251,7 @@ jobs:
         uses: codecov/codecov-action@v3
         with:
           flags: unittests
+          fail_ci_if_error: true
 
   # run database upgrade tests
   upgrade_test:
@@ -273,7 +264,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v3
         with:
-          go-version: "1.18"
+          go-version: "stable"
           cache: true
       - name: Build upgrade-tests
         run: go build ./cmd/dendrite-upgrade-tests
@@ -293,7 +284,7 @@ jobs:
       - name: Setup go
         uses: actions/setup-go@v3
         with:
-          go-version: "1.18"
+          go-version: "stable"
           cache: true
       - name: Build upgrade-tests
         run: go build ./cmd/dendrite-upgrade-tests
@@ -317,19 +308,9 @@ jobs:
           - label: SQLite Cgo
             cgo: 1
 
-          - label: SQLite native, full HTTP APIs
-            api: full-http
-
-          - label: SQLite Cgo, full HTTP APIs
-            api: full-http
-            cgo: 1
-
           - label: PostgreSQL
             postgres: postgres
 
-          - label: PostgreSQL, full HTTP APIs
-            postgres: postgres
-            api: full-http
     container:
       image: matrixdotorg/sytest-dendrite
       volumes:
@@ -338,7 +319,6 @@ jobs:
         - /root/.cache/go-mod:/gopath/pkg/mod
       env:
         POSTGRES: ${{ matrix.postgres && 1}}
-        API: ${{ matrix.api && 1 }}
         SYTEST_BRANCH: ${{ github.head_ref }}
         CGO_ENABLED: ${{ matrix.cgo && 1 }}
     steps:
@@ -390,22 +370,9 @@ jobs:
           - label: SQLite Cgo
             cgo: 1
 
-          - label: SQLite native, full HTTP APIs
-            api: full-http
-            cgo: 0
-
-          - label: SQLite Cgo, full HTTP APIs
-            api: full-http
-            cgo: 1
-
           - label: PostgreSQL
             postgres: Postgres
             cgo: 0
-
-          - label: PostgreSQL, full HTTP APIs
-            postgres: Postgres
-            api: full-http
-            cgo: 0
     steps:
       # Env vars are set file a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on env to run Complement.
       # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
@@ -447,7 +414,7 @@ jobs:
             (wget -O - "https://github.com/matrix-org/complement/archive/$BRANCH_NAME.tar.gz" | tar -xz --strip-components=1 -C complement) && break
           done
       # Build initial Dendrite image
-      - run: docker build --build-arg=CGO=${{ matrix.cgo }} -t complement-dendrite:${{ matrix.postgres }}${{ matrix.api }}${{ matrix.cgo }} -f build/scripts/Complement${{ matrix.postgres }}.Dockerfile .
+      - run: docker build --build-arg=CGO=${{ matrix.cgo }} -t complement-dendrite:${{ matrix.postgres }}${{ matrix.cgo }} -f build/scripts/Complement${{ matrix.postgres }}.Dockerfile .
         working-directory: dendrite
         env:
           DOCKER_BUILDKIT: 1
@@ -459,8 +426,7 @@ jobs:
         shell: bash
         name: Run Complement Tests
         env:
-          COMPLEMENT_BASE_IMAGE: complement-dendrite:${{ matrix.postgres }}${{ matrix.api }}${{ matrix.cgo }}
-          COMPLEMENT_DENDRITE_API: ${{ matrix.api && 1 }}
+          COMPLEMENT_BASE_IMAGE: complement-dendrite:${{ matrix.postgres }}${{ matrix.cgo }}
           COMPLEMENT_SHARE_ENV_PREFIX: COMPLEMENT_DENDRITE_
         working-directory: complement
 
diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 2e17539d..0c3053a5 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -61,7 +61,6 @@ jobs:
           cache-to: type=gha,mode=max
           context: .
           build-args: FLAGS=-X github.com/matrix-org/dendrite/internal.branch=${{ env.BRANCH }} -X github.com/matrix-org/dendrite/internal.build=${{ env.BUILD }}
-          target: monolith
           platforms: ${{ env.PLATFORMS }}
           push: true
           tags: |
@@ -77,7 +76,6 @@ jobs:
           cache-to: type=gha,mode=max
           context: .
           build-args: FLAGS=-X github.com/matrix-org/dendrite/internal.branch=${{ env.BRANCH }} -X github.com/matrix-org/dendrite/internal.build=${{ env.BUILD }}
-          target: monolith
           platforms: ${{ env.PLATFORMS }}
           push: true
           tags: |
@@ -98,86 +96,6 @@ jobs:
         with:
           sarif_file: "trivy-results.sarif"
 
-  polylith:
-    name: Polylith image
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      packages: write
-      security-events: write # To upload Trivy sarif files
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Get release tag & build flags
-        if: github.event_name == 'release' # Only for GitHub releases
-        run: |
-          echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
-          echo "BUILD=$(git rev-parse --short HEAD || \"\")" >> $GITHUB_ENV
-          BRANCH=$(git symbolic-ref --short HEAD | tr -d \/)
-          [ ${BRANCH} == "main" ] && BRANCH=""
-          echo "BRANCH=${BRANCH}" >> $GITHUB_ENV
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      - name: Login to Docker Hub
-        uses: docker/login-action@v2
-        with:
-          username: ${{ env.DOCKER_HUB_USER }}
-          password: ${{ secrets.DOCKER_TOKEN }}
-      - name: Login to GitHub Containers
-        uses: docker/login-action@v2
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Build main polylith image
-        if: github.ref_name == 'main'
-        id: docker_build_polylith
-        uses: docker/build-push-action@v3
-        with:
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-          context: .
-          build-args: FLAGS=-X github.com/matrix-org/dendrite/internal.branch=${{ env.BRANCH }} -X github.com/matrix-org/dendrite/internal.build=${{ env.BUILD }}
-          target: polylith
-          platforms: ${{ env.PLATFORMS }}
-          push: true
-          tags: |
-            ${{ env.DOCKER_NAMESPACE }}/dendrite-polylith:${{ github.ref_name }}
-            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:${{ github.ref_name }}
-
-      - name: Build release polylith image
-        if: github.event_name == 'release' # Only for GitHub releases
-        id: docker_build_polylith_release
-        uses: docker/build-push-action@v3
-        with:
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-          context: .
-          build-args: FLAGS=-X github.com/matrix-org/dendrite/internal.branch=${{ env.BRANCH }} -X github.com/matrix-org/dendrite/internal.build=${{ env.BUILD }}
-          target: polylith
-          platforms: ${{ env.PLATFORMS }}
-          push: true
-          tags: |
-            ${{ env.DOCKER_NAMESPACE }}/dendrite-polylith:latest
-            ${{ env.DOCKER_NAMESPACE }}/dendrite-polylith:${{ env.RELEASE_VERSION }}
-            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:latest
-            ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:${{ env.RELEASE_VERSION }}
-
-      - name: Run Trivy vulnerability scanner
-        uses: aquasecurity/trivy-action@master
-        with:
-          image-ref: ghcr.io/${{ env.GHCR_NAMESPACE }}/dendrite-polylith:${{ github.ref_name }}
-          format: "sarif"
-          output: "trivy-results.sarif"
-
-      - name: Upload Trivy scan results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@v2
-        with:
-          sarif_file: "trivy-results.sarif"
-
   demo-pinecone:
     name: Pinecone demo image
     runs-on: ubuntu-latest
diff --git a/.github/workflows/schedules.yaml b/.github/workflows/schedules.yaml
index fa2304c1..44758850 100644
--- a/.github/workflows/schedules.yaml
+++ b/.github/workflows/schedules.yaml
@@ -24,19 +24,8 @@ jobs:
           - label: SQLite Cgo
             cgo: 1
 
-          - label: SQLite native, full HTTP APIs
-            api: full-http
-
-          - label: SQLite Cgo, full HTTP APIs
-            api: full-http
-            cgo: 1
-
           - label: PostgreSQL
             postgres: postgres
-
-          - label: PostgreSQL, full HTTP APIs
-            postgres: postgres
-            api: full-http
     container:
       image: matrixdotorg/sytest-dendrite:latest
       volumes:
@@ -45,7 +34,6 @@ jobs:
         - /root/.cache/go-mod:/gopath/pkg/mod
       env:
         POSTGRES: ${{ matrix.postgres && 1}}
-        API: ${{ matrix.api && 1 }}
         SYTEST_BRANCH: ${{ github.head_ref }}
         RACE_DETECTION: 1
         COVER: 1
@@ -93,7 +81,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v3
         with:
-          go-version: '>=1.19.0'
+          go-version: 'stable'
           cache: true
       - name: Download all artifacts
         uses: actions/download-artifact@v3
@@ -125,22 +113,9 @@ jobs:
           - label: SQLite Cgo
             cgo: 1
 
-          - label: SQLite native, full HTTP APIs
-            api: full-http
-            cgo: 0
-
-          - label: SQLite Cgo, full HTTP APIs
-            api: full-http
-            cgo: 1
-
           - label: PostgreSQL
             postgres: Postgres
             cgo: 0
-
-          - label: PostgreSQL, full HTTP APIs
-            postgres: Postgres
-            api: full-http
-            cgo: 0
     steps:
       # Env vars are set file a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on env to run Complement.
       # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
@@ -182,7 +157,7 @@ jobs:
             (wget -O - "https://github.com/matrix-org/complement/archive/$BRANCH_NAME.tar.gz" | tar -xz --strip-components=1 -C complement) && break
           done
       # Build initial Dendrite image
-      - run: docker build --build-arg=CGO=${{ matrix.cgo }} -t complement-dendrite:${{ matrix.postgres }}${{ matrix.api }}${{ matrix.cgo }} -f build/scripts/Complement${{ matrix.postgres }}.Dockerfile .
+      - run: docker build --build-arg=CGO=${{ matrix.cgo }} -t complement-dendrite:${{ matrix.postgres }}${{ matrix.cgo }} -f build/scripts/Complement${{ matrix.postgres }}.Dockerfile .
         working-directory: dendrite
         env:
           DOCKER_BUILDKIT: 1
@@ -203,8 +178,7 @@ jobs:
         shell: bash
         name: Run Complement Tests
         env:
-          COMPLEMENT_BASE_IMAGE: complement-dendrite:${{ matrix.postgres }}${{ matrix.api }}${{ matrix.cgo }}
-          COMPLEMENT_DENDRITE_API: ${{ matrix.api && 1 }}
+          COMPLEMENT_BASE_IMAGE: complement-dendrite:${{ matrix.postgres }}${{ matrix.cgo }}
           COMPLEMENT_SHARE_ENV_PREFIX: COMPLEMENT_DENDRITE_
           COMPLEMENT_DENDRITE_COVER: 1
           COMPLEMENT_POST_TEST_SCRIPT: /tmp/posttest.sh
@@ -229,7 +203,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v3
         with:
-          go-version: '>=1.19.0'
+          go-version: 'stable'
           cache: true
       - name: Download all artifacts
         uses: actions/download-artifact@v3