[OCI] Feature to upload container images

[Vincinator]

What would you like to be added

Container images must also be uploaded to the OCI Index via the OCI delivery gear.

Migrating to single package name is a separate task that we first need to verify if this is required.

Container images that will be placed to the OCI Index eventually:

• package build container
• kernel driver build container
• base container for users (current gardenlinux container)
• test container

Why is this needed

• Sign referenced container digests
• Single place to check for completeness
• Signature verification of all components before creating open component model for Garden Linux release.
  • containers are part of the release, they are re-build for each release
    • kernel driver build container requires the correct kernel headers used for the respective image (mapped via version)
    • package build container requires the correct apt sources configured for the respective image (mapped via version)
    • base container has the same apt packages (mapped via version)

Notes

We do not migrate the OCI delivery target to the package name gardenlinux just yet, and we will keep the current way of publishing container images in place until we want to migrate.