Revenge should be informed or notified if it was taken by someone else

If something like this is to be implemented, I think it makes most sense as an "inbox" type of thing. Just so it pops up whenever you're back.

- Scripted knowledge of 'revenge' or 'threat' status is not reliable due to the fact that the game is unreliable in reporting damage and attacker/victims, especially when it comes to vehicle damage.
  - Even if partial support were to be added, it would be misleading in some situations where damage wasn't detected.