Tracking issue for SQLAlchemyReader

[FishmanL]

I figure it's mentioned in a bunch of other issues and doesn't yet have a tracking issue.

Also, my team specifically could really use a SQLAlchemyReader (or a MySqlReader) because Postgres's architecture is difficult for our use case (it's multiprocess/fork based and that interacts poorly with our hardware setup)

[joshua-oss]

FYI, we added a MySqlReader in smartnoise-sql==0.2.9. CI in GitHub Actions still isn't working, but CI tests in local MySql all are passing.