Initially the PiHole module was supposed to provide an option to expose rootless PiHole on privileged ports s.t. the user does not have to find out/decide how to do it herself.
However, it seems to be out-of-scope for flake which should provide a rootless PiHole container.
Further, any decision taken on how to achieve this could limit the users choices for other system configuration options.
Inestead options for making PiHole available on priviledged ports should be described in the Readme and maybe in example configurations.
The first part of the refactor simplifies the logic in the module and hides functions which are only used to extract container env vars.
Second the option renaming to piholeConfig unifies the naming with the hostConfig option.
This is necessary because podman-stop did not wait until the container was actually deleted and `RestartSec=` does not apply if the service is restarted by systemd itself (via restart).
RestartSec only applies if the restart reason is covered by `Restart=`
Currently the container often fails to startup again in a nixos-rebuild.
Maybe this is because the container lingers a bit after the systemd.service has already been stopped and the container from the restarted service can't be created.
The podman-stop command should delay the stopping of the service until the container is gone too.
