Remove dependency on django-autocomplete-light

[rebmizrahi]

Currently, I use django-autocomplete-light for html elements for selecting an object from the database. It is used multiple times in the form. It has caused me many problems as the html is weird, particularly when duplicated (see the multiple contributor forms), and should definitely be replaced by native html, which I don't think is too complicated but it also must be implemented as a custom django widget which I have not been able to figure out.

But, it works fine for now.