Allow each server to restrict commands to a specific channel

[skyegallup]

Certain commands, such as $showqueue, contain information that should be kept somewhat private. Restricting sensitive commands like these to a specific channel would allow server administrators to ensure that the privacy of their users will not be violated.

Perhaps create a custom role that stores a channel ID (e.g. MentorChannel:<base64 channel ID>)? This allows us to keep on our trend of storing all persistent per-server data in the server's role list itself, thus not requiring a separate database solution.

[peterkos]

What exactly is private about that command; usernames?

[skyegallup]

This one was @Madrugaur's suggestion, if I recall correctly. His reasoning was that showing who was in what queue was relatively personal information, though he may be able to justify that better.