Run CI tests against all multiple databases

[Floppy]

Because there are some variations in databases (see PRs #2449 and #2448 for examples), we should test against them all in our CI, perhaps in a nightly or pre-release task, not the regular build.

The test should run the standard and migration test suites (see #3363) with all the databases/version combinations listed below. We should test against anything that's officially supported, as shown on the relevant https://endoflife.date page. The table below shows the state as at the time of writing.

Database	Versions
SQLite3	built-in version only, covered by standard test setup
PostgreSQL	13, 14, 15, 16, 17
MySQL	8.0, 8.4, 9.1
MariaDB	10.5, 10.6, 10.11, 11.4, 11.6
Redis	7.4, 7.2, 6.2
Valkey	7.2

Presumably, we can use some sort of github actions matrix test setup to bring up the required database, set DATABASE_URL (or REDIS_URL), then run the test suite.

[julianharty]

Would you like to also test on various releases of operating systems? or are the issues more likely to be solely a factor of the database product and the database release?

[Floppy]

Good point - there's a bullet in #3364 about testing on different architectures, I've added OS to that.