[Feature Request] Make common settings configurable in docker-compose.yml

[fleimgruber]

When self-hosting GeoNetwork Docker containers, the Catalog Server Host and Port need to be changed in most cases. These settings can be changed as documented using the Webinterface: https://docs.geonetwork-opensource.org/4.2/administrator-guide/configuring-the-catalog/system-configuration/#catalog-description. It would be convenient to configure e.g. the hosting domain via an environment variable from docker-compose.yml so that a deployment can be specified and documented there instead of requiring manual one-off interaction with the webapp after deployment.