Additional fields for Disk structure
Additional fields for Disk structure

This adds the following new fields to the 'Disk' protobuf structure:
"disk_tech", "usage", "diskgroup_key", "model_key" and "vsan_policy_key"
to provide additional properties for disk objects in Aquilon.

Addresses-Issue: Jira/AQUILON-6506

quattor/aquilon-protocols,quattor/aquilon-protocols