Add importMode and set it to PreserveOriginal to import (#144)

manifestlisted image

Similar to
openshift/cluster-samples-operator#482, we want
CVO managed imagestreams to have the importMode as preserveOriginal so
that it imports the manifestlisted image with all arches so that it
works on a multi-arch compute cluster

manifests/01-openshift-imagestream.yaml

@@ -13,12 +13,14 @@ spec:
   - name: latest
     importPolicy:
       scheduled: true
+      importMode: PreserveOriginal
     from:
       kind: DockerImage
       name: example.com/image-reference-placeholder:driver-toolkit
   - name: 0.0.1-snapshot-machine-os 
     importPolicy:
       scheduled: true
+      importMode: PreserveOriginal
     from:
       kind: DockerImage
       name: example.com/image-reference-placeholder:driver-toolkit