Mark the oauth2_provider models as being managed by Django's migrations.

Review Request #1689 — Created July 4, 2019 and updated — Latest diff uploaded

Review Board
Review Board 3.0 shipped with a dependency on a specific version of
`oauth2_provider`, which provided some database models. Recent versions
of `oauth2_provider` have made updates, through Django's migrations. The
current version had migrations as well, but we weren't running a version
of Django that used them. This meant that we were missing a bit of
migration history, which causes conflicts when Django tries to apply
migrations on top of the synced models.

This adds some custom evolutions that tells Django Evolution that we
want to use migrations for this module, and which migrations would have
been applied at the transition point if its models were already synced.

Testing Done:
Created and upgraded databases successfully against Django 1.11.

Reviewed at