#6012 avoid a surprise by keep notice of a change

Newly joined client is now informed of lobby info and every client
present in lobby is informed of changes made by admin.
Using SendMessage results in the message being sent to every player in the lobby. Hence when a player joins everyone will get the lobby info messages again. But you are right the 'Server:' prefix needs to be there in order to prevent confusion between lobby info messages and the Admin's actual chat messages. Hence I'm still using SendOrderTo but with order as "Message"