Project Maintenance, Drop old versions and bring in line with AA slightly
Been a while since a major django-esi shakeup, we are still testing and maintaining "support" for eol versions of django.
- Drop dj32, 40 and 41. Maintain 42 and 50.
- Drastically cut down on test matrix
- update precommit to match AA
- add an isort config (unused)
When this is merged we would storm the repo with a pyupgrade/django-upgrade and any other formatting detected by precommit