Add ability to reset XP

[Mis4meow]

Add ability to reset a user's XP or clear an entire channel of XP

[xqus]

When you say clear an entire channel do you mean XP for everybody in that channel?

[Mis4meow]

Yes, to reset the entire channel. But the ability to reset XP for channels, people, the entire server, and people who have left is necessary.

[xqus]

Partially fixed by 5b8c079

[xqus]

• Clear individual user
• Clear the entire server This will be added to the dashboard
• Clean up by clearing users who have left