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.
