libimage artifact support shared between CRI-O and Podman

[saschagrunert]

CRI-O will add experimental artifact management (pull, list, inspect, remove) support in https://github.com/cri-o/cri-o/pull/8996, which should land in v1.33. In addition, we also like to add artifact mount support similar to https://github.com/containers/podman/pull/25397 to support artifacts in image volume mounts (https://github.com/kubernetes/enhancements/issues/4639).

Podman added artifact support in 5.4, but has generally a broader set of features, like artifact push and extract.

We should find the similarities in the implementations and move common code to this library when the features are considered as somewhat stable.

cc @bitoku