Merge pull request #19016 from smarterclayton/mirror

Automatic merge from submit-queue (batch tested with PRs 18905, 18968, 19016, 19037, 19056).

Clean up mirror and support quay.io pushing

quay.io doesn't have schema2 support yet, tolerate it in oc image mirror. Also add file support.

Does some preparator refactoring for adding parallel pushing support.

Author: openshift-merge-robot

contrib/completions/bash/oc

@@ -395,6 +395,7 @@
       "vendor/github.com/docker/docker",
       "vendor/github.com/docker/go-connections",
       "vendor/github.com/docker/go-units",
+      "vendor/github.com/docker/libtrust",
       "vendor/github.com/evanphx/json-patch",
       "vendor/github.com/fsnotify/fsnotify",
       "vendor/github.com/fsouza/go-dockerclient",