Made a asmdef for CommunicatorObjects (#3500)

* Made a asmdef for CommunicatorObjects

* Organized the communicator files into a separate folder

com.unity.ml-agents/Editor/Unity.ML-Agents.Editor.asmdef

     "name": "Unity.ML-Agents.Editor",
     "references": [
         "Unity.ML-Agents",
-        "Barracuda"
+        "Barracuda",
+        "Unity.ML-Agents.CommunicatorObjects"
+    "optionalUnityReferences": [],
     "includePlatforms": [
         "Editor"
     ],
     "precompiledReferences": [],
     "autoReferenced": true,
-    "defineConstraints": [],
-    "versionDefines": [],
-    "noEngineReferences": false
-}
+    "defineConstraints": []
+}

com.unity.ml-agents/Runtime/Unity.ML-Agents.asmdef

 {
     "name": "Unity.ML-Agents",
     "references": [
-        "Barracuda"
+        "Barracuda",
+        "Unity.ML-Agents.CommunicatorObjects"
     ],
     "optionalUnityReferences": [],
     "includePlatforms": [],
     ],
     "autoReferenced": true,
     "defineConstraints": []
-}
+}

com.unity.ml-agents/Tests/Editor/Unity.ML-Agents.Editor.Tests.asmdef

     "references": [
         "Unity.ML-Agents.Editor",
         "Unity.ML-Agents",
-        "Barracuda"
+        "Barracuda",
+        "Unity.ML-Agents.CommunicatorObjects"
     ],
     "optionalUnityReferences": [
         "TestAssemblies"
     "defineConstraints": [
         "UNITY_INCLUDE_TESTS"
     ]
-}
+}

com.unity.ml-agents/Runtime/Communicator.meta

+fileFormatVersion: 2
+guid: 432bb08962b3944c6964c0db6af43669
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

com.unity.ml-agents/Runtime/Grpc/AssemblyInfo.cs

+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Unity.ML-Agents")]
+[assembly: InternalsVisibleTo("Unity.ML-Agents.Editor")]
+[assembly: InternalsVisibleTo("Unity.ML-Agents.Editor.Tests")]

com.unity.ml-agents/Runtime/Grpc/AssemblyInfo.cs.meta

+fileFormatVersion: 2
+guid: 54959ce8e2e574f09b91f80a516acee3
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

com.unity.ml-agents/Runtime/Grpc/Unity.ML-Agents.CommunicatorObjects.asmdef

+{
+    "name": "Unity.ML-Agents.CommunicatorObjects",
+    "references": [],
+    "optionalUnityReferences": [],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [
+        "System.IO.Abstractions.dll",
+        "Google.Protobuf.dll",
+        "Grpc.Core.dll"
+    ],
+    "autoReferenced": true,
+    "defineConstraints": []
+}

com.unity.ml-agents/Runtime/Grpc/Unity.ML-Agents.CommunicatorObjects.asmdef.meta

+fileFormatVersion: 2
+guid: 61c5b659adf544b4baf3eef86248e13a
+AssemblyDefinitionImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: