Enable docker registry to clean untagged revisions
Enable docker registry to clean untagged revisions

As registry v2.7.1 has introduced the possibility to clean untagged manifests,
enable it in the registryctl api.

Signed-off-by: wang yan <63b20dea16c07a874bc9bf767df5575676113cb6@vmware.com>

steven-zou/harbor,steven-zou/harbor,steven-zou/harbor,reasonerjt/harbor,wy65701436/harbor,reasonerjt/harbor,steven-zou/harbor,wy65701436/harbor,steven-zou/harbor,wy65701436/harbor,reasonerjt/harbor,wy65701436/harbor,wy65701436/harbor,wy65701436/harbor,steven-zou/harbor,reasonerjt/harbor,reasonerjt/harbor,reasonerjt/harbor