Rename best classification attribute to high_confidence

arkindex/documents/admin.py

arkindex/documents/api/elements.py

arkindex/documents/api/entities.py

arkindex/documents/api/ml.py

...x/documents/migrations/0030_rename_classification_best.py

arkindex/documents/models.py

arkindex/documents/serializers/ml.py

arkindex/documents/tests/test_bulk_classification.py

arkindex/documents/tests/test_classes.py

arkindex/documents/tests/test_moderation.py