In https://github.com/metabrainz/listenbrainz-server/pull/1421/ we made a start towards allowing LB to start up if the timescale service is unavailable. In this case, we start up as normal but when a user tries to visit a page that requires timescale we return an error message.

We should extend this process to also allow LB to start up if other services are down (main postgres, redis, rabbitmq), and show a relevant error message on each page.

This would have to be combined with a check that informs us if a service is down, because the regular http status check on listenbrainz.org would still succeed