Support updated OCI multi-arch image in Harbor

ref: https://goharbor.io/blog/harbor-2.8/

> [OCI Distribution Spec v1.1.0-rc1 Support](https://github.com/opencontainers/image-spec/releases/tag/v1.1.0-rc1)The latest Harbor release now supports the OCI Distribution Spec v1.1.0-rc1. This is a significant upgrade that allows users to store and distribute OCI and Docker images. With this feature, users can manage their images more effectively and efficiently.
>
> https://github.com/goharbor/harbor/pull/18324https://github.com/goharbor/harbor/pull/18369https://github.com/goharbor/harbor/pull/18394

After #1712, we need to support the above new features of Harbor.Also, let's refactor `ai.backend.manager.container_registry` subpkg to have a reactive handlers for different manifest media types.

JIRA Issue: BA-177