dataImportCronTemplates: Move default-instancetype to u1.medium (#2397)

common-instancetypes v0.3.0 as deployed by SSP operator v0.18.1 renames
the N neutral instance type class to U for universal ahead of new
network related classes being introduced in a future release.

This change moves the dataImportCronTemplates used by the SSP operator
over to this new class. It also corrects a previous mistake, using the
correct `u1.medium` name of the resource. A follow up change will
provide some basic functional testing of this to ensure a mistake like
this isn't able to merge in the future.

This change is backwardly compatible, any previous users of the N
instance type class either directly through their VirtualMachine
definition or indirectly inferred through these default
labels will not be impacted with their VirtualMachines continuing to use
the original N instance type class.

Signed-off-by: Lee Yarwood <lyarwood@redhat.com>

assets/dataImportCronTemplates/dataImportCronTemplates.yaml

@@ -4,7 +4,7 @@
     name: centos-stream8-image-cron
     labels:
       instancetype.kubevirt.io/default-preference: centos.8.stream
-      instancetype.kubevirt.io/default-instancetype: n.medium
+      instancetype.kubevirt.io/default-instancetype: u1.medium
   spec:
     schedule: "0 */12 * * *"
     template:
@@ -24,7 +24,7 @@
     name: centos-stream9-image-cron
     labels:
       instancetype.kubevirt.io/default-preference: centos.9.stream
-      instancetype.kubevirt.io/default-instancetype: n.medium
+      instancetype.kubevirt.io/default-instancetype: u1.medium
   spec:
     schedule: "0 */12 * * *"
     template:
@@ -44,7 +44,7 @@
     name: fedora-image-cron
     labels:
       instancetype.kubevirt.io/default-preference: fedora
-      instancetype.kubevirt.io/default-instancetype: n.medium
+      instancetype.kubevirt.io/default-instancetype: u1.medium
   spec:
     schedule: "0 */12 * * *"
     template:
@@ -64,7 +64,7 @@
     name: centos-7-image-cron
     labels:
       instancetype.kubevirt.io/default-preference: centos.7
-      instancetype.kubevirt.io/default-instancetype: n.medium
+      instancetype.kubevirt.io/default-instancetype: u1.medium
   spec:
     schedule: "0 */12 * * *"
     template: