Implement a rollback system for most system features.

[RealistikDash]

This is a quite broad feature but it would allow the easy rolling back of edits these kinds of edits:

• Level updates
• Level ratings
• User stats
• User comments (partially implemented)
  The rollaback should be its own command (and most importantly, the rollback should be able to be rolled back). Also, needs a pretty comprehensive mod action system.