* Move Tox tool config settings to pyproject.toml
* Restore older Bandit version for predictive setup
Bandit UX is seriously broken. Unfortunately, only <1.6 works predictably.
* Exclude unsupported Python/Django combinations
Use a more self-explanatory build job name for tests
* Help pytest find the Django test project settings
* Use clean range for Django 4.0
* Keep load on the GHA runners low, use newer Python for checks