Main changes:
- Multiple Galaxy objects can now exist at the same time in DB. This allows for ruling a new galaxy while still
displaying the old one.
- The criteria to quickly know whether a user is a possible citizen is now a simple query on picture count. This
avoids a very complicated query to database, that could often result in huge working memory load. With this change,
it should be possible to run the galaxy even on a vanilla Postgres that didn't receive fine tuning for the Sith's
galaxy.
