Related issue: https://github.com/heptio/velero/issues/1830
This accomplishes everything
that's needed, although there might be room for improvement in avoiding
a GET call for matching CRDs for each resource backed up. An alternative
could be a single call to get all CRDs prior to iterating over resources
and passing this into the backupResource function.
Signed-off-by: Scott Seago <sseago@redhat.com>