AzureDevOpsDsc: Support publish wiki documentation

[johlju]

Pull Request (PR) description

• AzureDevOpsDsc
  • Added pipeline support for publish markdown content to the GitHub repository wiki (issue #15). This will publish the markdown documentation that is generated bu the build pipeline.
  • Added new source folder WikiSource. Every markdown file in the folder WikiSource will be published to the GitHub repository wiki. The markdown file Home.md will be updated with the correct module version on each publish to gallery (including preview).
  • Updated pipeline file RequiredModules.ps1 to latest pipeline pattern.
  • Updated pipeline file build.yaml to latest pipeline pattern.
• AzDevOpsProject
  • Added description to the comment-based help.
  • Added a validate set to the parameter SourceControlType to (for now) limit the parameter to the values Git and Tfvc.
  • Update comment-based help to remove text which the valid values are since that is now add automatically to the documentation (conceptual help and wiki documentation).

This Pull Request (PR) fixes the following issues

• Fixes #15

Task list

• [x] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [x] Resource documentation updated in the resource's README.md.
• [ ] Resource parameter descriptions updated in schema.mof.
• [ ] Comment-based help updated, including parameter descriptions.
• [ ] Localization strings updated.
• [ ] Examples updated.
• [ ] Unit tests updated. See DSC Community Testing Guidelines.
• [ ] Integration tests updated (where possible). See DSC Community Testing Guidelines.
• [x] Code changes adheres to DSC Community Style Guidelines.

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This change is 

[johlju]

@SphenicPaul small one to enable Wiki publish and also limit the property SourceControlType to the two valid values (the values will show up automatically in the conceptual help and wiki doc).

[johlju]

Integration tests cannot run until merged to main.