Outdated Guide for Installing Velero on Supervisor Cluster

[yuyin002]

Describe the bug

[A clear and concise description of what the bug is]

The guide for installing Velero on Supervisor Cluster is outdated and no long applicable
https://github.com/vmware-tanzu/velero-plugin-for-vsphere/blob/main/docs/velero-vsphere-operator-user-manual.md#installing-velero-on-supervisor-cluster
It requires updates as soon as possible, since it is a blocker for customers' Supervisor Backup Restore workflow.

To Reproduce

[Steps to reproduce the behavior]
Follow the guide, we cannot find the 'Velero vSphere Operator Service' on the UI and thus cannot install Velero Operator Service.

Expected behavior

[A clear and concise description of what you expected to happen]
With the guide, users should be able to successfully install Velero into Supervisor Cluster.

Troubleshooting Information

[Please refer to the Troubleshooting page and collect the required information]

Screenshots
No Velero Operator Service available (VC version 8.0)

[If applicable, add screenshots to help explain your problem.]

Anything else you would like to add:

[Miscellaneous information that will assist in solving the issue]

[xing-yang]

Before the doc is updated, please take a look of the attached doc:
Enable Velero vSphere Operator.pdf