Adds /me command. (#414)

* Adds /me command.

* Update Content.Server/Chat/ChatManager.cs

Co-Authored-By: Pieter-Jan Briers <pieterjan.briers@gmail.com>

Content.Server/Interfaces/Chat/IChatManager.cs

@@ -15,6 +15,7 @@ namespace Content.Server.Interfaces.Chat
         void DispatchServerMessage(IPlayerSession player, string message);
 
         void EntitySay(IEntity source, string message);
+        void EntityMe(IEntity source, string action);
 
         void SendOOC(IPlayerSession player, string message);