Add a new load_default_connections in the Core configuration of Airflow, similar to load_examples but aimed at avoiding the creation of default Connections in airflow/utils/db.py.
By default it should be retrocompatible:
- the default behaviour should be the old behaviour (True)
- the old behaviour should also be kept in the CI tests and other places were configuration is used
The config should be documented as being new.
See also in the Helm charts project, concerning the stable/airflow chart:
> [stable/airflow] Add a feature to run extra init scripts in the scheduler after initdb