Accelerator Documentation and remove hard-coded rg values

[oZakari]

Overview/Summary

GitHub Issue: #492
ADO: AB#17187

Adds initial documentation for the ALZ Bicep Accelerator and updates consumer guide to include the Accelerator as an implementation option.

This PR fixes/adds/changes/removes

1. Adds initial documentation for the ALZ Bicep Accelerator
2. Updates consumer guide to include the Accelerator as an implementation option.
3. Removed hardcoded rg names from PowerShell scripts and replaced with env variables

Breaking Changes

None, only updating documentation.

Testing Evidence

Not applicable as only related to documentation.

As part of this Pull Request I have

• Read the Contribution Guide and ensured this PR is compliant with the guide
• Ensured the resource API versions in .bicep file/s I am adding/editing are using the latest API version possible
• 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

[oZakari]

The lint error is because the file I am referencing is the README for the accelerator.

[oZakari]

Added last minute adjustment to remove couple hard-coded rg names. Good spot @stalejohnsen and thanks!

[jtracey93]

/azp run validateazcloud

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