Remove temporary annotations and labels used by mig-controller

[sseago]

cloned fusor/ocp-velero-plugin#51 to new repo

Mig controller uses temporary annotations and labels to identify resources staged for backup. These annotations are added to the resources on the source cluster before backup begins and are removed once the backup finishes. However, Velero's backup still has them in the backup file making them re-appear on the destination as the resources are restored. Velero Plugin should remove those annotations and labels since they are of no use.

The temporary annotations used are -
backup.velero.io/backup-volumes=list_of_volumes

openshift.io/migrate-type=

Temporary label is -
openshift.io/pv-backup-<MigPlan_UID>:true

[sseago]

fusor/ocp-velero-plugin#52 will need to be recreated in the new repo.