Remove EntityRole and EntityLink models

arkindex/documents/admin.py

arkindex/documents/api/entities.py

arkindex/documents/export/__init__.py

arkindex/documents/export/entity_link.sql

arkindex/documents/export/entity_role.sql

arkindex/documents/export/indexes.sql

arkindex/documents/export/structure.sql

arkindex/documents/fixtures/data.json

arkindex/documents/management/commands/load_export.py

arkindex/documents/management/commands/merge_entities.py

...documents/migrations/0010_delete_entityrole_entitylink.py

arkindex/documents/models.py

arkindex/documents/serializers/entities.py

arkindex/documents/tasks.py

arkindex/documents/tests/commands/test_load_export.py

arkindex/documents/tests/commands/test_merge_entities.py

arkindex/documents/tests/tasks/test_corpus_delete.py

arkindex/documents/tests/tasks/test_export.py

arkindex/documents/tests/test_entities.py

arkindex/documents/tests/test_entities_api.py