[Bug 699530] Sanitizer now drops tables that we don't want to copy to dev/stage

This is to handle the tables we don't want to copy over because they contain metadata that might mess things up in stage/dev environments.

I'm not sure what some of these tables are even used for, maybe some of them need to go away permanently? Like I don't think we're even using database sessions, so django_session probably should go away... and I don't know what the taskboard_* tables are for...