Update defaultRestorePriorities for CSI resources

[nrb]

When restoring a CSI volume, the following resources should be restored before PVCs, in order to properly hook up references:

• volumesnapshotcontents.snapshot.storage.k8s.io
• volumesnapshot.snapshot.storage.k8s.io
• volumesnapshoclass.snapshot.storage.k8s.io

A more complete list looks like this:

var defaultRestorePriorities = []string{
    "namespaces",
    "storageclasses",
    "customresourcedefinitions",
    "volumesnapshotclass.snapshot.storage.k8s.io",
    "volumesnapshotcontents.snapshot.storage.k8s.io",
    "volumesnapshots.snapshot.storage.k8s.io",
    "persistentvolumes",
    "persistentvolumeclaims",
    "secrets",
    "configmaps",
    "serviceaccounts",
    "limitranges",
    "pods",
    "replicaset",
}

[skriss]

For the prototype phase, we should consider just having users use the --restore-resource-priorities flag on the velero server command to configure this.

[nrb]

Yeah, that’s totally reasonable.

I’ll update docs and move this out of the v1.1 milestone.