Add way to check permissions client-side (#880)

Added IClientConGroupController and implemented it as ClientConGroupController. Lets client-side code check what commands the client can use based on their console group. Serves the same purpose as the server-side IConGroupController except it doesn't load a list of permissions from groups.yml. Instead,  the server ConGroupController sends updated permissions to clients whenever they change.

Robust.Client/ClientIoC.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using Robust.Client.Console;
 using Robust.Client.Debugging;
 using Robust.Client.GameObjects;
@@ -127,6 +127,7 @@ namespace Robust.Client
 #endif
 
             IoCManager.Register<ISignalHandler, ClientSignalHandler>();
+            IoCManager.Register<IClientConGroupController, ClientConGroupController>();
         }
     }
 }