Cleanup user model

I removed a shitton of fields which aren't used anymore.  A long time ago.  So here it is now.

I really wanted to fix the waifu system to be a simpler relation (`belongs_to :waifu, class_name: 'Character'`), but we have to discuss how to link a character to their franchise or primary anime before we can stop doing the crazy Casting-based system.  Otherwise we're stuck with a shitty N+1 or broken APIv1 compatibility.