SBOM & Access Log: Pull info for rescan decision logic

See related issue for more information.

1. Check if manifest exists for name:tag (has this tag been published already) skopeo inspect ...

   • If not, no diff needed: new tag
   • Save the labels from the old mainfest
   • Idea: move code from lint stage (skopeo_inspect_base_image) to a module - pass name/tag

2. Check if the git sha in the old labels is different

   • If different, no diff needed: new commit
   • Digest for most recent commit.
   • Label in skopeo inspect output: org.opencontainers.image.revision

3. Check if the parent digest changed (will need to inspect the parent too to get it's new digest)

   • If different, no diff needed: updated parent

Added: Extract original build date (another label to pull out)