Refactoring: rename covid19 to flask_covid19

src/flask_covid19/__init__.py

src/flask_covid19/blueprints/app_all/all_config.py

src/flask_covid19/blueprints/app_all/all_service.py

src/flask_covid19/blueprints/app_web/web_services.py

src/flask_covid19/blueprints/app_web/web_views.py

src/flask_covid19/blueprints/data_divi/divi_service.py

...flask_covid19/blueprints/data_divi/divi_service_import.py

...flask_covid19/blueprints/data_divi/divi_service_update.py

src/flask_covid19/blueprints/data_divi/divi_test_service.py

src/flask_covid19/blueprints/data_divi/divi_test_views.py

src/flask_covid19/blueprints/data_divi/divi_views.py

src/flask_covid19/blueprints/data_rki_cases/rki_service.py

...k_covid19/blueprints/data_rki_cases/rki_service_import.py

...k_covid19/blueprints/data_rki_cases/rki_service_update.py

...ask_covid19/blueprints/data_rki_cases/rki_test_service.py

...flask_covid19/blueprints/data_rki_cases/rki_test_views.py

src/flask_covid19/blueprints/data_rki_cases/rki_views.py

...lueprints/data_rki_vaccination/rki_vaccination_service.py

...ts/data_rki_vaccination/rki_vaccination_service_import.py

...ts/data_rki_vaccination/rki_vaccination_service_update.py