- Prevent client that do not have appropriate capabilities to create chat

rooms
- Reply 488 Not Acceptable Here if a client without groupchat capabilities
tries to create a chatroom
- Do not send a SUBSCRIBE if the chatroom that has just been created has
an handler in the remote conference list event handler
- Reply 403 Forbidden if a client successfully creates a chatroom but he/she is not allowed in
- Do not subscribe again to chatrooms when refreshing a register

Tester: Add devices information only if they have groupchat capabilities
when registering a new ClientConference