Edits to run esap-db behind Traefik

This branch contains all the changes I did to run the esap-db at ASTRON per #12 (closed). Also I added one variable to the .env, which defines if the Traefik network should be created or expected to already exist, so that the tests can actually run on a node not running a Traefik instance. The side effect of this is that a network will be created for all deployments that do not run Traefik.