Reconcile govmomi / govc Dependencies

[jonathanmeier5]

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With the implementation of #2744 EKS-A now depends on both govmomi and govc, a CLI tool derived from the govmomi vSphere client.

We should reconcile these dependencies so we only rely on one.

One option is to convert all our govc calls to govmomi calls.

Another is to open a PR in to the govmomi project and add the functionality we need to the govc CLI.