The GOTK controllers all use an annotation to trigger syncing outside
of the schedule (e.g., when a webhook is indicates a new
revision). This commit makes the ImageRepository controller respect
the annotation, by checking it when examining an image repo object.
This works a little different to the other controllers, which tend to
assume that any incoming event means a sync is due. The image
reflector controller uses the ChangedPredicate to filter incoming
evetns, as they do, but goes further to check the annotation and
otherwise, the scheduled scan time.
In this commit I use the test registry implementation to check that
the controller will scan the tags of an image. This needs a bit more
scaffolding, since the test registry doesn't handle /tags/list.
Michael Bridgen