Database should be tuned and scaled with quay-app

[jtaleric]

Since the Operator ships with PostgreSQL we should make a best effort to tune the DB out of the box.
Some common tuning here[1].

However, we also should also ensure we open enough connections. From[2], and the default pool size of 20. We should look to have max_connections set to ~ 300. We should also make sure, if we scale the quay:app we should continue to increase the number of connections by 300.

[1] https://www.percona.com/blog/2018/08/31/tuning-postgresql-database-parameters-to-optimize-performance/
[2] https://github.com/quay/quay-operator/pull/31/files