Refactoring: vaccination

src/flask_covid19/blueprints/app_all/all_model.py

src/flask_covid19/blueprints/app_all/all_model_import.py

src/flask_covid19/blueprints/data_divi/divi_model_import.py

src/flask_covid19/blueprints/data_ecdc/ecdc_model_import.py

src/flask_covid19/blueprints/data_owid/owid_model_import.py

src/flask_covid19/blueprints/data_rki/rki_model_import.py

...9/blueprints/data_vaccination/vaccination_model_import.py

src/flask_covid19/blueprints/data_who/who_model.py

src/flask_covid19/blueprints/data_who/who_model_import.py