Azure backup DNS zone geo code fix and docs

[jtracey93]

Overview/Summary

Azure backup DNS zone geo code fix and docs

This PR fixes/adds/changes/removes

1. Updates privateDnsZone & hubNetworking module
2. Fixes 🪲 Bug Report - Azure Backup Private DNS Zones for Private Link Missing Geo Codes #279

Breaking Changes

Old Azure Backup Private DNS zone will need to be manually removed by users but new, correct, DNS zone will be created on incremental deployments.

Testing Evidence

Linting & Unit Tests will suffice

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).

[jfaurskov]

Seems to be missing a dns namespace in hubnetworking module

[jfaurskov]

LGTM