Add a nightly GH workflow that:

• reads and extract the OCI references from the extensions catalog entities that are baked into the existing index image (see the `spec.dynamicArtifact` fields)
• generates ImageStream manifests for the packages that are published to registry.redhat.io
• create a PR with the changes. We can even consider auto-approving it once we are confident with the changes over time.

The workflow should handle both main and release-1.y branches. For release-1.y branches, it should read from the right 1.y tag of the catalog index image. And for main, it should read from the latest 1.y tag

The workflow should also generate an ImageStream manifest for the plugin catalog index image itself.