chore: update product terms

[tenthirtyam]

Description

This pull request updates product terms to align with rebranding.

As of the release of vSphere 9.0 the following product names/terms have changed:

• vCenter Server >> vCenter
• vCenter Server instance >> vCenter instance
• ESXi >> ESX

[Copilot]

Pull Request Overview

This pull request updates product terminology throughout the codebase to align with VMware vSphere 9.0 rebranding. The changes replace outdated product names with their current versions according to the new naming conventions.

• Updates "vCenter Server" to "vCenter" and "vCenter Server instance" to "vCenter instance"
• Changes "ESXi" to "ESX" throughout documentation and code
• Renames the ESXiHost struct field to ESXHost while maintaining backward compatibility with the mapstructure tag

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
post-processor/vsphere/post-processor.hcl2spec.go	Updates struct field name from ESXiHost to ESXHost
post-processor/vsphere/post-processor.go	Updates field name, comments, and references from ESXi to ESX and vCenter Server to vCenter instance
post-processor/vsphere-template/post-processor.go	Updates comment reference from vCenter Server instance to vCenter instance
examples/builder/vsphere-iso/alpine/alpine.pkr.hcl	Updates datastore description comment from ESXi to ESX
docs/README.md	Updates documentation references from ESXi to ESX and vCenter Server to vCenter
Multiple documentation files	Updates product terminology in generated documentation files
builder/vsphere files	Updates comments and documentation from ESXi to ESX and vCenter Server to vCenter instance

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