Add MG Flexibility Feature & Intermediate Root MG Parent Flexibility

[jtracey93]

Overview/Summary

Add MG Flexibility Feature

This PR fixes/adds/changes/removes

1. Add MG Flexibility Feature
2. Add Intermediate Root MG Parent Flexibility

Breaking Changes

None

Testing Evidence

Logic can be tested here at this link https://gist.github.com/jtracey93/eca6400dc97266d5313c93afc1670e2a

Linting and unit tests will test other parts of this PR.

I have also tested manually and was successful.

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Checked for duplicate Pull Requests
• Associated it with relevant GitHub Issues
• (ALZ Bicep Core Team Only) Associated it with relevant ADO Items
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated one or more of the following tests (if required)
  • Unit
  • Linting
  • E2E (End-To-End)
  • ValidateAzCloud (Base validation in Azure Cloud)
  • ValidateMcCloud (Base validation in Azure China Cloud)
• Updated relevant and associated documentation (e.g. Contribution Guide, Module READMEs, Wiki Docs etc.)
• If relevant, created or updated Code Tours here

[jtracey93]

/azp run validateazcloud

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jtracey93]

/azp run e2e

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jtracey93]

/azp run validateazcloud

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jtracey93]

/azp run e2e

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[JefferyMitchell]

@mblant Please review related to style guide discussion.