[build] Add several util units

Adds the following util units and adds them to libbitcoin_util:

- `util/url.cpp` takes `urlDecode` from `httpserver.cpp`
- `util/error.cpp` takes `TransactionErrorString` from
  `node/transaction.cpp` and `AmountHighWarn` and `AmountErrMsg` from
  `ui_interface.cpp`
- `util/fees.cpp` takes `StringForFeeReason` and `FeeModeFromString` from `policy/fees.cpp`
- `util/rbf.cpp` takes `SignalsOptInRBF` from `policy/rbf.cpp`
- 'util/validation.cpp` takes `FormatStateMessage` and `strMessageMagic` from 'validation.cpp`

1 files changed, 0 insertions, 34 deletions

diff --git a/src/policy/fees.cpp b/src/policy/fees.cpp
index c49b9fa36b..524afd014e 100644
--- a/src/policy/fees.cpp
+++ b/src/policy/fees.cpp
@@ -27,40 +27,6 @@ std::string StringForFeeEstimateHorizon(FeeEstimateHorizon horizon) {
     return horizon_string->second;
 }
 
-std::string StringForFeeReason(FeeReason reason) {
-    static const std::map<FeeReason, std::string> fee_reason_strings = {
-        {FeeReason::NONE, "None"},
-        {FeeReason::HALF_ESTIMATE, "Half Target 60% Threshold"},
-        {FeeReason::FULL_ESTIMATE, "Target 85% Threshold"},
-        {FeeReason::DOUBLE_ESTIMATE, "Double Target 95% Threshold"},
-        {FeeReason::CONSERVATIVE, "Conservative Double Target longer horizon"},
-        {FeeReason::MEMPOOL_MIN, "Mempool Min Fee"},
-        {FeeReason::PAYTXFEE, "PayTxFee set"},
-        {FeeReason::FALLBACK, "Fallback fee"},
-        {FeeReason::REQUIRED, "Minimum Required Fee"},
-        {FeeReason::MAXTXFEE, "MaxTxFee limit"}
-    };
-    auto reason_string = fee_reason_strings.find(reason);
-
-    if (reason_string == fee_reason_strings.end()) return "Unknown";
-
-    return reason_string->second;
-}
-
-bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode) {
-    static const std::map<std::string, FeeEstimateMode> fee_modes = {
-        {"UNSET", FeeEstimateMode::UNSET},
-        {"ECONOMICAL", FeeEstimateMode::ECONOMICAL},
-        {"CONSERVATIVE", FeeEstimateMode::CONSERVATIVE},
-    };
-    auto mode = fee_modes.find(mode_string);
-
-    if (mode == fee_modes.end()) return false;
-
-    fee_estimate_mode = mode->second;
-    return true;
-}
-
 /**
  * We will instantiate an instance of this class to track transactions that were
  * included in a block. We will lump transactions into a bucket according to their