(doc) Add/update docs for Chocolatey.PowerShell module

[vexx32]

Description Of Changes

Adds / updates docs for changes in https://github.com/chocolatey/choco/pull/3440

Motivation and Context

Twofold; one, new command, new docs. Two, the GenerateDocs.ps1 won't work for the new cmdlets and it would be hairy to tie them together. Instead, we're using PlatyPS to generate/maintain these docs, so they need to be in a separate folder (unfortunately).

I have retained the old links and xrefs from the original PowerShell Functions Reference page, so that all cmdlets can still be accessed from that index.

Eventually when everything has moved over to this new section as we progress with cmdlet rewrites, we can collapse the two sections back into one again.

Testing

• [x] I have previewed these changes using the Docker Container or another method before submitting this pull request.

Change Types Made

• [ ] Minor documentation fix (typos etc.).
• [x] Major documentation change (refactoring, reformatting or adding documentation to existing page).
• [x] New documentation page added.
• [ ] The change I have made should have a video added, and I have raised an issue for this.
  • Issue #

Change Checklist

• [x] Requires a change to menu structure (top or left-hand side)/
• [x] Menu structure has been updated

Related Issue

https://github.com/chocolatey/choco/pull/3440

[gep13]

@vexx32 thanks for getting this added, and to @st3phhays and @pauby for the reviews. I have enabled auto-merge so the PR will be merged once the CI build completes.