vmware: VM diagnostics (v3 API only)

There is no formal definition for the VM diagnostics. For the
V2 API the diagnostics will be returned as they are today.

This will support backward compatibility with the existing API's.

Part of the blueprint v3-diagnostics

DocImpact

Change-Id: I6465ee6fc2edac0107e260297d9647c8a16b09ae
Merge "vmware: VM diagnostics (v3 API only)"