gRPC support for account_tx and tx

- Add support for all transaction types and ledger object types to gRPC
  implementation of tx and account_tx.

- Create common handlers for tx and account_tx.

- Remove mutex and abort() from gRPC server. JobQueue is stopped before
  gRPC server, with all coroutines executed to completion, so no need for
  synchronization.

src/test/rpc/GRPCTestClientBase.h

@@ -20,7 +20,7 @@
 #ifndef RIPPLED_GRPCTESTCLIENTBASE_H
 #define RIPPLED_GRPCTESTCLIENTBASE_H
 
-#include <rpc/v1/xrp_ledger.grpc.pb.h>
+#include <org/xrpl/rpc/v1/xrp_ledger.grpc.pb.h>
 #include <test/jtx/envconfig.h>
 
 namespace ripple {
@@ -29,7 +29,7 @@ namespace test {
 struct GRPCTestClientBase
 {
     explicit GRPCTestClientBase(std::string const& port)
-        : stub_(rpc::v1::XRPLedgerAPIService::NewStub(grpc::CreateChannel(
+        : stub_(org::xrpl::rpc::v1::XRPLedgerAPIService::NewStub(grpc::CreateChannel(
               beast::IP::Endpoint(
                   boost::asio::ip::make_address(getEnvLocalhostAddr()),
                   std::stoi(port))
@@ -40,7 +40,7 @@ struct GRPCTestClientBase
 
     grpc::Status status;
     grpc::ClientContext context;
-    std::unique_ptr<rpc::v1::XRPLedgerAPIService::Stub> stub_;
+    std::unique_ptr<org::xrpl::rpc::v1::XRPLedgerAPIService::Stub> stub_;
 };
 
 }  // namespace test