Add tool generated PowerShell module

[Gijsreyn]

PR Summary

This change adds the initial scaffolding for the Microsoft.PowerShell.DSC PowerShell module. It contains two public functions to generate DSC resource manifest files.

The four functions are:

• New-DscAdaptedResourceManifest - parses class-based PowerShell DSC resources from three file types (.psd1, .ps1, or .psm1)
• New-DscResourceManifest - combines adapted resources (via pipeline) and/or command-based DSC resource (via -Resource) into a DscResourceManifestList object.
• Import-DscAdaptedResourceManifest - reads existing .dsc.adaptedResource.json files and returns DscAdaptedResourceManifest objects
• Import-DscResourceManifest - reads existing .dsc.manifests.json files and returns a DscResourceManifestList object with adapted resources, command-based resources, and extensions

Both functions support pipeline input and can be chained together. For example:

New-DscAdaptedResourceManifest -Path ./MyModule/MyModule.psd1 |
    New-DscResourceManifest |
    ForEach-Object { $_.ToJson() } |
    Set-Content -Path ./MyModule/MyModule.dsc.manifests.json

# Import an existing manifest list, add a new adapted resource, and re-export
$list = Import-DscResourceManifest -Path ./MyModule/MyModule.dsc.manifests.json
Import-DscAdaptedResourceManifest -Path ./NewResource.dsc.adaptedResource.json |
    ForEach-Object { $list.AddAdaptedResource($_) }
$list.ToJson() | Set-Content -Path ./MyModule/MyModule.dsc.manifests.json

Known limitations

This is the initial implementation as a starting point. Edge cases are definitely missed, and the module will need iteration. Known areas that I can think of that are not yet handled include:

• Complex nested class hierarchies beyond single-level inheritance (don't know if it's even possible in class-based DSC resources)
• Resources defined across multiple files that use using module
• Validation attributes
• More error handling for incorrect values/properties

PR Context

Partially addresses #1311

[Copilot]

Pull request overview

This PR introduces initial scaffolding for the Microsoft.PowerShell.DSC PowerShell module, focused on generating DSC v3 manifest content for class-based (adapted) resources and bundling them into a manifests list.

Changes:

• Adds New-DscAdaptedResourceManifest to parse PowerShell AST for [DscResource()] classes and emit adapted resource manifest objects with embedded JSON schema.
• Adds New-DscResourceManifest to aggregate adapted resources (pipeline) and/or command-based resources (-Resource) into a DscResourceManifestList with ToJson() serialization.
• Adds Pester tests and fixture modules/resources covering single/multi-resource modules, inheritance/enums, and basic JSON serialization.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tools/Microsoft.PowerShell.DSC/Microsoft.PowerShell.DSC.psm1	Implements manifest/schema generation logic and public functions.
tools/Microsoft.PowerShell.DSC/Microsoft.PowerShell.DSC.psd1	Adds module manifest exporting the two public functions.
tools/Microsoft.PowerShell.DSC/Tests/New-DscAdaptedResourceManifest.Tests.ps1	Adds Pester coverage for adapted manifest creation, schema embedding, and pipeline input.
tools/Microsoft.PowerShell.DSC/Tests/New-DscResourceManifest.Tests.ps1	Adds Pester coverage for bundling adapted/command resources and JSON serialization.
tools/Microsoft.PowerShell.DSC/Tests/Fixtures/*	Adds fixture modules/resources used by the Pester tests.

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