VMware: associate instance with storage policy

This is part of the blueprint vmware-spbm-support. This patch
associates an instance with a given storage policy, if defined.
This enables a vsphere admin to check if the instance is compliant
with the storage policy.

Co-authored-by: Radoslav Gerganov <rgerganov@vmware.com>
Co-authored-by: Gary Kotton <gkotton@vmware.com>

Change-Id: I79f8b165e2a82a7335f50f2a421b10e69c02c9f0
Merge "VMware: associate instance with storage policy"