refactor: move RpcBatcher under Messaging namespace and directory (#474)

Author: 0xFA11

com.unity.multiplayer.mlapi/Runtime/Core/RpcBatcher.cs renamed to com.unity.multiplayer.mlapi/Runtime/Messaging/RpcBatcher.cs

@@ -1,15 +1,14 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Collections.Generic;
 using MLAPI.Serialization.Pooled;
 using MLAPI.Serialization;
 using MLAPI.Configuration;
 using MLAPI.Profiling;
-using MLAPI.Messaging;
 using MLAPI.Transports;
-using System.Collections.Generic;
-using System.Linq;
-using System;
-using System.IO;
 
-namespace MLAPI
+namespace MLAPI.Messaging
 {
     internal class RpcBatcher
     {

com.unity.multiplayer.mlapi/Runtime/Core/RpcBatcher.cs.meta renamed to com.unity.multiplayer.mlapi/Runtime/Messaging/RpcBatcher.cs.meta

@@ -205,7 +205,7 @@ private void RPCQueueSendAndFlush()
         /// </summary>
         /// <param name="clientId"> clientId to send to</param>
         /// <param name="sendStream"> the stream to send</param>
-        private static void SendCallback(ulong clientId, MLAPI.RpcBatcher.SendStream sendStream)
+        private static void SendCallback(ulong clientId, RpcBatcher.SendStream sendStream)
         {
             var length = (int)sendStream.Stream.Length;
             var bytes = sendStream.Stream.GetBuffer();