Chat protocol rewrite (#5117)

* New TOCLIENT_CHAT_MESSAGE packet

* Rename old packet to TOCLIENT_CHAT_MESSAGE_OLD for compat
* Handle TOCLIENT_CHAT_MESSAGE new structure client side
* Client chat queue should use a specific object
* SendChatMessage: use the right packet depending on protocol version (not complete yet)
* Add chatmessage(type) objects and handle them client side (partially)
* Use ChatMessage instead of std::wstring server side

* Update with timestamp support

src/clientiface.h

@@ -434,6 +434,7 @@ public:
 
 	/* send to all clients */
 	void sendToAll(NetworkPacket *pkt);
+	void sendToAllCompat(NetworkPacket *pkt, NetworkPacket *legacypkt, u16 min_proto_ver);
 
 	/* delete a client */
 	void DeleteClient(u16 peer_id);