Add db cleanup function for easier debugging and testing of dags

### Description I think that a function that automatically truncates the `Airflow`'s can be beneficial for us to help us combine and manage the state of airflow with [`dag.test` and debugging dags](https://airflow.apache.org/docs/apache-airflow/stable/core-concepts/debug.html). ### Use case/motivation I want to have a function that I can call using my python code (mostly in my tests) to truncate the whole airflow db locally, it would only work in unit tests mode and on sqlite only (to avoid deleting production db). ### Related issues _No response_ ### Are you willing to submit a PR? - [x] Yes I am willing to submit a PR! ### Code of Conduct - [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)