[Sharded-Execution-GRPC] Add GRPC communication for sharded execution

In this commit we replace the existing socket based communication with GRPC.
Here we get the basic GRPC reliability.

More reliability and better performance to come in subsequent commits

crates/aptos-protos/proto/aptos/remote_executor/v1/network_msg.proto

@@ -0,0 +1,20 @@
+// Copyright © Aptos Foundation
+// SPDX-License-Identifier: Apache-2.0
+
+syntax = "proto3";
+
+package aptos.remote_executor.v1;
+
+message NetworkMessage {
+    string sender_addr = 1;
+    bytes message = 2;
+    string message_type = 3;
+}
+
+message Empty {
+
+}
+
+service RemoteExecution {
+    rpc SimpleMsgExchange(NetworkMessage) returns (Empty);
+}