[bug 935632] Add intermediary account creation

This creates a UserProfile model which doesn't do a whole lot yet other
than let us denote new users.

This updates all the places where the user's name shows up to use
get_display_name().

This adds a FjordVerify class which sends new users to the creation
page. Right now this is sort of a stub and allows us to create a
UserProfile. At some point p, this will be important and will have a
profile creation form and also tell the new user what he/she can do on
Input.
[bug 925973] Disable next button if description empty
Fix new-user view regarding AnonymousUser

This fixes the new-user view to handle AnonymousUser correctly rather
than error out.
Fix new_user so it ignores people with profiles