Integrate `unbase_oci` based on Podman

[NotTheEvilOne]

What would you like to be added:
unbase_oci is designed to streamline container images by eliminating unnecessary components inherited from the base container, thereby reducing bloat and enhancing security.

Why is this needed:
While the well working original is based on bash scripts to run a whole bunch of executables an well integrated successor utilizing gardenlinux.oci.PodmanContext() will well integrate with the focus of the python-gardenlinux-lib to streamline and support building Garden Linux images on all supported development environments.

[NotTheEvilOne]

While integration into python-gardenlinux-lib would be feasible the unbase_oci tool is suitable for use cases outside Garden Linux as well. Currently considering to separate our Podman logic from the python-gardenlinux-lib for reusability in the library as well as unbase_oci.