Build (or find) widget that can display a Searchable choice field in a form.

As we add generic facilities, it becomes apparent that for large numbers of facilities some better method is needed for selecting them from the DB over a choice field. 

We should have a form widget that allows for some form of searchable choice field or autocomplete suggestion.

These things exist (see https://github.com/yourlabs/django-autocomplete-light/) or we can write our own.