Changing signoff form and expose/hide button on the superevent
web display to make an AJAX request to the relevant API endpoints.
This way, we don't have to maintain separate permissions and views
for web resources.

Adding view functions, templates, and full nasty javascript
to get a more complete and (hopefully) temporary implementation
of the superevent detail view ready. This includes buttons for
allowing/removing LV-EM access and forms for signoffs.

Remove commented out code blocks for file handling in
superevents/forms.py.