Fixes #1013

#1013

I've splitted the userhandler and added two new functions: `delete_content` which deletes all "private" things like events, messages, draft etc and `delete_posts` which deletes all posts and threads. (No "real" changes, both were parts of `delete_user` before, which calls the functions now instead).
The purgespammer feature hasn't any indication now what will be deleted, if the user should be banned, it calls the functions above, bans the user and clears the profile. If the user should be deleted, it simply calls the `delete_user` function. I've moved the ban reason to the settings page and removed two templates.

If I've missed anything: cry. And please check this ASAP!
Shouldn't we use the datahandler `update_user()` method here? Unsure if it can be done.