Add vSphere Cluster API provider to the CLI

[dkrasins]

Implement a cluster provider for vSphere using Cluster API in the CLI.

Requirements

• The CLI needs a cluster provider (i.e. "ocne cluster start --provider vsphere")
• The management cluster must be able to host the vSphere-based clusters
• An alternate cluster must be able to host vSphere-based clusters
• A management cluster must be able to create vSphere-based clusters in multiple target clusters
• There must be the ability to create and publish OCK images for Kubevirt (i.e. "ocne image create --type vsphere" and "ocne image push ...")

Tasks

• [ ] #29
• [ ] #30
• [ ] #31
• [ ] #32