[Azoth] Service messages in chat tab even with sep MUC log.
[Azoth] Refactored ProcessOutgoingMsg() out of ChatTab.

Use ProxyObject to append the message, way more universal.
[Azoth MuC] MuCommands module stubs.
[Azoth] Added IProvideCommands for #1000.
[Azoth MuC] Implement IProvideCommand with /names for #1000.
[Azoth] Query IProvideCommands for commands for #1000.
[Azoth MuC] Refactored stuff into commands file.