[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, 4 deletions

diff --git a/src/policy/fees.h b/src/policy/fees.h
index c8472a12f5..6e61f76178 100644
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -46,8 +46,6 @@ enum class FeeReason {
     MAXTXFEE,
 };
 
-std::string StringForFeeReason(FeeReason reason);
-
 /* Used to determine type of fee estimation requested */
 enum class FeeEstimateMode {
     UNSET,        //!< Use default settings based on other criteria
@@ -55,8 +53,6 @@ enum class FeeEstimateMode {
     CONSERVATIVE, //!< Force estimateSmartFee to use conservative estimates
 };
 
-bool FeeModeFromString(const std::string& mode_string, FeeEstimateMode& fee_estimate_mode);
-
 /* Used to return detailed information about a feerate bucket */
 struct EstimatorBucket
 {