Remove the "misc antags" preference

[robertGN]

Both Werewolf and Rev head are currently under misc antags, and should probably be individually toggleable. Is there any chance we could just drop the non-descriptive and ultimately useless "misc antags" preference option and instead give all antagonists a toggle?

I don't mind being a Rev Head, but I would rather not additionally enable an entirely rampage-based antagonist in order to get it.