squashed some bugs and added MITM_SUPPORT_INFO.md

MITM_SUPPORT_INFO.md

README.md

superset/commands/mitm/mitm_dataset/create.py

superset/commands/mitm/mitm_dataset/delete.py

superset/commands/mitm/mitm_service/get.py

...commands/mitm/mitm_service/schemas/mitm_service_schema.py

superset/commands/mitm/mitm_service/upload.py

superset/commands/mitm/mitm_service/visualizations.py

...omization/external_service_support/forwardable_request.py

superset/customization/mitm_datasets/api.py

superset/tasks/mitm/upload_mitm_dataset.py

tests/requests/mitm_dataset_api.http