We need a testing tips docs page

[goodboy]

Was just talking with a collaborator and we definitely need a page on how to run and monitor the tests.

Tips i can think of offhand:

• for monitoring the process tree while the test suite runs: watch -n 0.5 'pstree -a $(pgrep pytest)' ~- the celery remote debugger can be super handy for debugging crashed sub-actors~ now already solved with our built-in version 🥳 for the most part.

More to come..