instead of overriding IPs for existing DNS records, to reduce suprises
when DNS records are different depending on the host.
Add metronom + tankstelle internal wireguard IPs, too.
This works towards having reusable modules
* `config.pub-solar-os.networking.domain` is used for the main domain
* `config.pub-solar-os.privacyPolicUrl` links towards the privacy policy
* `config.pub-solar-os.imprintUrl` links towards the imprint
* `config.pub-solar-os.auth.enable` enables the keycloak installation.
This is needed because `config.pub-solar-os.auth` has to be available
everywhere, but we do not want to install keycloak everywhere.
* `config.pub-solar-os.auth.realm` sets the keycloak realm name