Badge Request: Harbor Image Registry

:clipboard: **Description**

Support size and version badges for docker images hosted in private [harbor image registry].(https://github.com/goharbor/harbor)

:link: **Data**
https://github.com/goharbor/harbor

:microphone: **Motivation**

Many companies managed private harbor registries for internal usage.

The issue identifies Harbor as the service and requests private-registry image size and version badges, but it names no repository files, tests, or API entry point. First determine how existing registry badges obtain authenticated data; done means both requested badge types work for private Harbor image registries and have coverage for their returned values.

Written by the indexing model from the issue text.