Move GitHub and File Operation functionality to Modules

[Trenly]

📖 Description

This PR refactors YamlCreate support logic into dedicated, reusable PowerShell modules.

What changed

• Added Tools/Modules/YamlCreate/YamlCreate.GitHub/:
  • YamlCreate.GitHub.psd1
  • YamlCreate.GitHub.psm1
  • YamlCreate.GitHub.Tests.ps1
• Added Tools/Modules/FileOperations/:
  • FileOperations.psd1
  • FileOperations.psm1
  • FileOperations.Tests.ps1
• Updated Tools/YamlCreate.ps1 and Tools/Modules/YamlCreate/YamlCreate.psd1 to use these shared modules instead of inlined implementation details.

Why this change was made

• Maintainability: Separating GitHub and file system concerns into focused modules reduces coupling inside YamlCreate.ps1, making future updates safer and easier to reason about.
• Readability: Smaller, responsibility-driven modules are easier to navigate than a single script containing mixed concerns.
• Reusability: Common operations now live in importable modules, so other tooling can consume the same functionality without duplicating logic.
• Testability and reliability: Module-scoped tests were added with the modules, enabling targeted validation of behavior where the logic now lives.

Forward-looking impact

A potential follow-up PR can reuse these same modules from Tools/SandboxTest.ps1, helping consolidate shared behavior across tooling and avoid parallel implementations.

✅ Checklist

• Signed the Contributor License Agreement
• Linked to an issue (if applicable)
  • No linked issue.

📦 Manifest Checklist

• Checked that there aren't other open pull requests for the same manifest update/change (N/A: non-manifest tooling PR)
• This PR only modifies one (1) manifest (N/A: non-manifest tooling PR)
• Validated manifest locally with winget validate --manifest (validation guide) (N/A: non-manifest tooling PR)
• Tested manifest locally with winget install --manifest (N/A: non-manifest tooling PR)
• Manifest conforms to the 1.12 schema (N/A: non-manifest tooling PR)

Note

is the directory containing the manifest you're submitting. This PR does not submit or modify manifests.

[Trenly]

cc @mdanish-kh

[denelon]

[denelon]

I'm not sure what's going on with this one...

[Trenly]

I'm not sure what's going on with this one...

I can try a rebase to get it up to date