Add support for RedHat 9

[cbaxley]

🗣 Description

#563
Adds support for RedHat 9

💭 Motivation and context

RedHat is used by many organizations, so support was added for a current version.

🧪 Testing

Create a redhat instance using the azure builder using this command and run installer and tests as usual:

./azure/build_azure_linux_network.py -g $RESOURCE_GROUP -s $PUBLIC_IP -vs $VM_SIZE -l $LOCATION -ast $AUTO_SHUTDOWN_TIME --use-rhel

✅ Pre-approval checklist

• Changes are limited to a single goal AND
  the title reflects this in a clear human readable format
• Issue that this PR solves has been selected in the Development section
• I have read and agree to LME's CONTRIBUTING.md document.
• The PR adheres to LME's requirements in RELEASES.md
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated to reflect the changes in this PR.

✅ Pre-merge Checklist

• All tests pass
• PR has been tested and the documentation for testing is above
• Squash and merge all commits into one PR level commit

✅ Post-merge Checklist

• Delete the branch to keep down number of branches