Add basic administrative functionality

[rbreslow]

Commands:

• [ ] Ban
• [ ] Ban IP
• [ ] Kick
• [ ] Unban
• [ ] Map
• [ ] Mute (Prevent text/voice chat)
• [ ] Unmute
• [ ] Modify Rank

Functionality:

• Show how many admins are online.
• Have a way of DMing an admin.
• Wish List: VGUI for executing these commands, listing bans.

[johnnymoe]

Administrators should have full privileges. Let's delegate the following to moderators:

1. Ban
2. Ban IP
3. Kick
4. Unban
5. Mute
6. Unmute