Fix
* fix(db): Database access refactor (676)
* feat: Remove global sessions, and introduce read only sessions for cases where no writing is required
* refactor: Rename db to session
* feat: Raise exceptions if commit/write/delete is attempted on a read-only session
* feat: Add tests for the read only session
* chore: lint using flake8
* rename test_database -> db_engine
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Co-authored-by: Richard Abrich <richard.abrichgmail.com> ([`987f6ac`](https://github.com/OpenAdaptAI/OpenAdapt/commit/987f6acc55c1512805ab0cc31c922cb17c1cc846))