Remove every trace of hsqldb. Having it locally but running mysql in production is misguided.
It is still misguided. Just too much work at this point.

Revert "Remove every trace of hsqldb. Having it locally but running mysql in production is misguided."

This reverts commit 0ca480e726e12cf1483349be146f0deea23829d6.
have nice logging at development-time again
the antiquated version of flyway swallows stacktraces without logging them, so we must do it ourselves.