Merge branch 'cleanup_databases' into 'django3_migration'

beat/web/databases/__init__.py

beat/web/databases/admin.py

beat/web/databases/api.py

beat/web/databases/apps.py

beat/web/databases/exceptions.py

beat/web/databases/migrations/0001_initial.py

beat/web/databases/migrations/0002_scheduler_addons.py

beat/web/databases/migrations/0003_auto_20160704_1316.py

...eb/databases/migrations/0004_beat_backend_python_1_5_x.py

...b/databases/migrations/0005_databaseset_data_migration.py

.../web/databases/migrations/0006_databaseset_hash_unique.py

beat/web/databases/migrations/0007_add_accessibility_date.py

beat/web/databases/models.py

beat/web/databases/serializers.py

beat/web/databases/signals.py

beat/web/databases/templates/databases/list.html

beat/web/databases/templates/databases/panels/actions.html

beat/web/databases/templates/databases/panels/table.html

beat/web/databases/templatetags/database_tags.py

beat/web/databases/tests.py