Validate '|' cannot be in a password

http://manage.dimagi.com/default.asp?60104

Monkey patches set_password. Displays "'|' is not allowed in a password" as the error in all three possible locations.
Also
- you should replace all occurrences of `SetPasswordForm` with this one (I'm thinking https://github.com/dimagi/commcare-hq/blob/6bf8f263181b4c41bfdde845dee0ee74523a6d32/corehq/apps/users/views/mobile/users.py#L90, even though there's probably no function change, those should just logically be the same form)
- move this to `users/forms.py`