Add SQLite CI testing job

[adrianthedev]

Let's add SQLite to our CI pipeline.
Just with rails main, not with all the variants.

Also, let's monitor to see if the tests run faster. If so, maybe we do it the other way around where the matrix runs on Lite and one runs on PG

[github-actions]

This issue has been marked as stale because there was no activity for the past 15 days.