Reset models to use Element

src/arkindex/api_v1.py

src/documents/admin.py

src/documents/api.py

src/documents/apps.py

src/documents/importer.py

src/documents/managers.py

src/documents/migrations/0001_initial.py

src/documents/models.py

src/documents/serializers.py

src/documents/tests.py

src/documents/views.py

src/images/importer.py

src/images/migrations/0001_initial.py

src/images/models.py