Update generator migration script to be a PowerShell script (#51110)

* Initial plan

* Initial plan for migrating Python script to PowerShell

Co-authored-by: JoshLove-msft <54595583+JoshLove-msft@users.noreply.github.com>

* Add PowerShell version of Library_Inventory script and update documentation

Co-authored-by: JoshLove-msft <54595583+JoshLove-msft@users.noreply.github.com>

* Add Library_Inventory.json to .gitignore and complete migration

Co-authored-by: JoshLove-msft <54595583+JoshLove-msft@users.noreply.github.com>

* Revert .gitignore change - script only creates JSON on explicit request

Co-authored-by: JoshLove-msft <54595583+JoshLove-msft@users.noreply.github.com>

* Remove obsolete Python script after migration to PowerShell

Co-authored-by: live1206 <5196139+live1206@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: JoshLove-msft <54595583+JoshLove-msft@users.noreply.github.com>
Co-authored-by: live1206 <5196139+live1206@users.noreply.github.com>

Author: 3 people