refactor: Consistency when importing generic views from django.views.generic

As discussed in commit comments on !67 (merged), it seems that the "more proper" pattern for importing Django's generic views is to import them from django.views.generic, rather than specifying django.views.generic.base or django.views.generic.edit (et al). Beyond Django explicitly supporting this methodology in django.views.generic.__init__ and using this methodology in its docs concerning generic views, this will also help us keep all of our template imports onto one line - it's win-win-win.

Therefore, this MR applies the same methodological logic to the only other place in the codebase where we're importing views in this manner - tordonate.views, to be precise.