Refactor cmake (#1231)

Fixes #920.

src/rpc/CMakeLists.txt

@@ -0,0 +1,44 @@
+add_library(clio_rpc)
+
+target_sources(
+  clio_rpc
+  PRIVATE Errors.cpp
+          Factories.cpp
+          AMMHelpers.cpp
+          RPCHelpers.cpp
+          Counters.cpp
+          WorkQueue.cpp
+          common/Specs.cpp
+          common/Validators.cpp
+          common/MetaProcessors.cpp
+          common/impl/APIVersionParser.cpp
+          common/impl/HandlerProvider.cpp
+          handlers/AccountChannels.cpp
+          handlers/AccountCurrencies.cpp
+          handlers/AccountInfo.cpp
+          handlers/AccountLines.cpp
+          handlers/AccountNFTs.cpp
+          handlers/AccountObjects.cpp
+          handlers/AccountOffers.cpp
+          handlers/AccountTx.cpp
+          handlers/AMMInfo.cpp
+          handlers/BookChanges.cpp
+          handlers/BookOffers.cpp
+          handlers/DepositAuthorized.cpp
+          handlers/GatewayBalances.cpp
+          handlers/Ledger.cpp
+          handlers/LedgerData.cpp
+          handlers/LedgerEntry.cpp
+          handlers/LedgerRange.cpp
+          handlers/NFTsByIssuer.cpp
+          handlers/NFTBuyOffers.cpp
+          handlers/NFTHistory.cpp
+          handlers/NFTInfo.cpp
+          handlers/NFTOffersCommon.cpp
+          handlers/NFTSellOffers.cpp
+          handlers/NoRippleCheck.cpp
+          handlers/Random.cpp
+          handlers/TransactionEntry.cpp
+)
+
+target_link_libraries(clio_rpc PRIVATE clio_util)