Add hidden commands for admin purposes

[wick2o]

This pull request will allow users to have administrative/hidden commands. These commands will not show up in the help card and will only be allowable to a approved user list, much like the approved_rooms variable. Otherwise the bot will not respond to them.

When creating a new command you can specify the following:

approved_admins=self.cfg['approved_admins'] admin_command=True,

For questions I can be reached directly here: [email protected].