ThumbnailFileInput -> KanisaThumbnailFileWidget
The form for modifying users is no longer a ModelForm

This'll make it easier to add permission changes
Fixing overly long line
Permission text shouldn't end with a full stop
Add something like crispy_forms InlineCheckboxes

This version basically has one option per line, which is
better for longer lists of things.
Add a note about staff/superuser
Allow editing permissions from our user editing view
I broke this test when I made files compulsory

Fixing requires mock, but I should probably use mock more
anyway.