Users should be able to completely delete their account, like any sane service.
[ ] API
[ ] Web
Add a `deleteUser` func that takes a `User` and `bool` on whether or not to delete all the user's posts. Should remove all user traces from:
Removes collection traces:
Removes posts if user wanted it:
Deletes external accounts when they're entirely based on logging in with Write.as, e.g. Snap.as currently.