Add OCI Artifact Conversion and Push Support

[akashsinghal]

Proposed Functionality Additions:

• Add CLI support in the obdconv command for converting DADI OCI Image to a new DADI OCI Artifact
• Add original unconverted image as a subject referrer in the Artifact
• Push the Artifact to specified OCI Artifact compliant registry

[BigVan]

I saw the code in your personal repo a few days ago. Would you mind opening a PR in this project and we will ask other core members to review it?

[akashsinghal]

@BigVan Thanks for checking in. The current implementation is being optimized to include some new changes made to the ORAS go module. We will make the PR as soon as it’s completed.