Add command pack manifest push to push an manifest list to a remote registry

[jjbustamante]

Context

We've been working on the idea to add multi-arch support on CNB. A mentorship project was created on LFX and this feature is part of the efforts to build the Minimal Viable Product (MVP) during the program duration.

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Description

When a user already has a manifest list saved in the docker daemon, they require to push that manifest list (Image Index) to a remote registry.

Proposed solution

A new feature on Pack can be implemented to help our users. The feature is inspired by the similar functionality in docker or podman

pack manifest push [OPTIONS] <manifest-list> 

Push a manifest list to a repository

  options:
          --format      Manifest list type (oci or v2s2) to use when pushing the list (default is v2s2)
          --insecure   Allow push to an insecure registry
     -p --purge       Delete the manifest list or image index from local storage if pushing succeeds.

Describe alternatives you've considered

Additional context

• This feature should be documented somewhere