UpdateServicesComputerTargetGroup: (new resource) Computer Target Group Creation / Deletion

[oliveirt]

Pull Request (PR) description

This Pull Request (PR) fixes the following issues

Task list

• [x] Added an entry under the Unreleased section of the change log in the CHANGELOG.md. Entry should say what was changed, and how that affects users (if applicable).
• [x] Resource documentation added/updated in README.md.
• [x] Resource parameter descriptions added/updated in README.md, schema.mof and comment-based help.
• [x] Comment-based help added/updated.
• [x] Localization strings added/updated in all localization files as appropriate.
• [x] Examples appropriately added/updated.
• [x] Unit tests added/updated. See DSC Resource Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Resource Testing Guidelines.
• [x] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

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This change is 

[Borgquite]

@gaelcolas @johlju What would be needed to revive this repository and specifically this pull request? I can do some smaller updates if it’s just rotted due to subsequent updates…

[johlju]

@Borgquite do you have time to review this PR? If you feel it looks okay to you I will merge it.

[johlju]

This PR also need to be rebased. I tried to do it, but there were a lot of conflicts, to many for me to have time to fix. So either if @oliveirt can rebase, or if @Borgquite maybe you can send in a new PR?