Fix tests, modernize Tox config, and use Python to generate test MaxMind database

[blag]

Description

Tests were not working on my machine, so I fixed them.
I also updated the Tox config to only test versions of Python and Django that were still supported by upstream. Except for Django 4.2, since support for that ends in about only six weeks.
Lastly, instead of using a Perl script wrapped in a Docker image to generate the MMDB files for tests, I converted that to a Python script.

Motivation and Context

Tests now run (again), and our test process is simplified and dependencies minified.

How Has This Been Tested?

All tests run and pass.

Types of changes

• Administrative changes

Checklist:

• My code follows the code style of this project.
• All new and existing tests passed.

[blag]

Hold off on merging this just yet, looking into an issue with mmdb-writer.

[WhyNotHugo]

Ack

[blag]

Okay, I figured out how to test out using country MMDB files and enabled that. This PR should be ready to merge after review. Thank you for your patience.