web_api_key: initial port to Flask.
- Moves web_api_key logic to the model.
- Refactors functions to work with sqlalchemy and flask request.
- Refactors web_api_key to work with model functions.
- Updates web_api_key_regression_tests.
- Adds a decorator api_key_required for authentication through an api_key.
Signed-off-by: Konstantinos Ntemagkos <konstantinos.ntemagkos@cern.ch>
Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>