rpc: Register calls where they are defined

Split out methods to every module, apart from 'help' and 'stop' which
are implemented in rpcserver.cpp itself.

- This makes it easier to add or remove RPC commands - no longer everything that includes
    rpcserver.h has to be rebuilt when there's a change there.
- Cleans up `rpc/server.h` by getting rid of the huge cluttered list of function definitions.
- Removes most of the bitcoin-specific code from rpcserver.cpp and .h.

Continues #7307 for the non-wallet.

src/rpc/rawtransaction.cpp

@@ -841,3 +841,23 @@ UniValue sendrawtransaction(const UniValue& params, bool fHelp)
 
     return hashTx.GetHex();
 }
+
+static const CRPCCommand commands[] =
+{ //  category              name                      actor (function)         okSafeMode
+  //  --------------------- ------------------------  -----------------------  ----------
+    { "rawtransactions",    "getrawtransaction",      &getrawtransaction,      true  },
+    { "rawtransactions",    "createrawtransaction",   &createrawtransaction,   true  },
+    { "rawtransactions",    "decoderawtransaction",   &decoderawtransaction,   true  },
+    { "rawtransactions",    "decodescript",           &decodescript,           true  },
+    { "rawtransactions",    "sendrawtransaction",     &sendrawtransaction,     false },
+    { "rawtransactions",    "signrawtransaction",     &signrawtransaction,     false }, /* uses wallet if enabled */
+
+    { "blockchain",         "gettxoutproof",          &gettxoutproof,          true  },
+    { "blockchain",         "verifytxoutproof",       &verifytxoutproof,       true  },
+};
+
+void RegisterRawTransactionRPCCommands(CRPCTable &tableRPC)
+{
+    for (unsigned int vcidx = 0; vcidx < ARRAYLEN(commands); vcidx++)
+        tableRPC.appendCommand(commands[vcidx].name, &commands[vcidx]);
+}