Tweak tests and template data - testing philosophy

[kelle]

Right now, the tests actually modify the database. I think this is undesirable behavior. Tests should either undo modifications they make to the database or NOT make them. The tests should use database content and I don't think need to test database modification. (Astrodb_utils does the database modification tests.)

[kelle]

I also want to minimize the number of fake sources in the template data. I'd like to delete a bunch of the data which are added during the tests.

[kelle]

partially done in #73

[kelle]

Thinking about this in the context of tests we want users to run:

I think we should do some basic db editing to make sure things work. Add a source/delete it. Add a publication/delete it. Anything else?

I think we should test both the direct way and the astrodb_utils helper functions.

Make a dedicated test_astrodb_utils.py. Test load_db, find/ingest source, find/ingest publication.