Merge cmd_{connect,server,squit} into a single stub module.
Rewrite cmd_admin in preparation for converting to core modules.

- Configuration is now stored in the module rather than the core.
- Changed some things to comply better with RFC1459.
Rewrite cmd_quit in preparation for converting to core modules.

- Configuration is now stored in the module rather than the core.
- OperQuit extension is now registered by the module instead of the core.
Rewrite cmd_part in preparation for converting to core modules.

- Configuration is now stored in the module rather than the core.