[EPIC] Support VM Remote Backup and Restore with Third-Party Storage

[WebberHuang1118]

Is your feature request related to a problem? Please describe (👍 if you like this request)

Support VM remote backup and restore with Third-Party Storage

Describe the solution you'd like

We could design a dedicated Harvester controller using a data engine like Restic or Kopia to provide built-in backup and restore functionality. Alternatively, we could publish a knowledge base article (KB) on how to use Velero with the KubeVirt Velero plugin.

Describe alternatives you've considered

Export a volume as a VM image and reuse it across any Harvester cluster.

Additional context

No response

[innobead]

cc @harvester/storage

[ihcsim]

Following discussion at harvester/harvesterhci.io#85, some design consideration is needed for the restoration of virtual machine images, to avoid conflicts with CDI. Likely, we will have to sequence the restore such that the golden image PVC is restored first, then restore the CDI data volume to "adopt" the golden image PVC via claim adoption. Then finally, restore the virtual machine image manifest.