Add vSphere metrics to report vCenter version

[Danil-Grigorev]

What would you like to be added:

We need reporting of vSphere vCenter version to be shown in the metrics.

Why is this needed:

The goal behind this is to add some info about the underlying infrastructure for the kubernetes cluster. Some customers were experiencing issues during the cluster upgrades, but nothing in the upgrades themselves or kubernetes code for vSphere provider seemingly could cause those. The issue is storage related, and happening on a variety of releases with a significant delay from any other underlying infrastructure change, to which the kubernetes cluster has no relation and a way to know about. So knowing used vCenter hostnames, and vSphere versions associated with it over time would be extremely beneficial for debugging in similar circumstances.

Some of the use cases we face:

1. A vSpehre DRS is enabled in a customer environment, and so there occurs a periodic automated vMotion for VMs backing kuberentes Nodes. We'd like to know on which host the actual kubernetes Node was located at any moment, and if any vCenter version transitions happened over time, new hosts added/removed/renamed.

[Danil-Grigorev]

/sig cloud-provider
/wg provider-vsphere

[k8s-ci-robot]

@Danil-Grigorev: The label(s) wg/provider-vsphere cannot be applied, because the repository doesn't have them

In response to this:

/sig cloud-provider
/wg provider-vsphere

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[Danil-Grigorev]

/area provider/vmware