ADGroup: add SamAccountName parameter

[gaelicWizard]

Pull Request (PR) description

Adds optional parameter SamAccountName to ADGroup resource to allow setting this property separately. This requires that GroupName be specified using something other than the SamAccountName, e.g. SID, DN, UPN, &c.

This Pull Request (PR) fixes the following issues

• See #655

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).
• [ ] 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.
• [ ] Examples appropriately added/updated.
• [x] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

---

This change is 

[codecov[bot]]

Codecov Report

Merging #658 (11a3dd5) into main (9346a1d) will increase coverage by 0%. The diff coverage is 100%.

@@         Coverage Diff         @@
##           main   #658   +/-   ##
===================================
  Coverage    98%    98%           
===================================
  Files        25     25           
  Lines      3408   3412    +4     
===================================
+ Hits       3340   3344    +4     
  Misses       68     68           

[X-Guardian]

PR #651 must be merged before this PR and it will then need refactoring.