This is a quick commit. I gave admins the ability to ban or unban users

straight from the moderation.users_detail page. I also changed the
UserBan.expiration_date type from DateTime into Date. I also began work on the
Terms of Service, pulled from another website (which will be cited clearly
before I'm done). I added new tests as well for the ban/unbanning. Lastly,
I added a few `user_not_banned` decorators to relevant views, so banned users
cannot access any pages.

mediagoblin/submit/views.py

@@ -125,6 +125,7 @@ def submit_start(request):
 
 
 @require_active_login
+@user_not_banned
 def add_collection(request, media=None):
     """
     View to create a new collection