[WIP] experimental support for vm-operator-api

[MartinWeindel]

What this PR does / why we need it:
vSphere 7 with Kubernetes will allow to use the Kubernetes-based "VM Operator API" to create virtual machines.
This PR is an ongoing effort to enable the vSphere provider alternatively with the new api.

See also vm-operator-api

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Release note:

experimental support of vm-operator-api

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