Create release pipelines for publishing images

[SteveLasker]

Move the currently built image from https://hub.docker.com/r/notaryv2/registry to an oras-artifacts specific hub org.

[SteveLasker]

Looking at the other oras packages, these are published on ghcr: https://github.com/orgs/oras-project/packages

Suggest we publish distribution here as well
https://github.com/orgs/oras-project/packages/distribution
this would generate a package that would be consumed as:

docker pull ghcr.io/oras-project/distribution:artifacts-v1

[sajayantony]

The official image is called registry so I would recommend we align with that and have ensure a full alpha build.
ghcr.io/oras-project/registry:v1.0-alpha

[SteveLasker]

registry makes sense. Suggest we tag it something that aligns with either the main release + something specific to the enabled artifact support. This way we can merge back into main of distribution.

[sajayantony]

• @avtakkar

[SteveLasker]

just capturing the release of artifact support should be put under a feature flag. This way it can merge back to main and consumers can opt into the behavior when they complete their implementation. for indexing