Allow AD group in Remote LZ as AKS Cluster Admin

[lukecalderon-dca]

1256 - Feature request - Remote AD Group for AKS Admin Groups

PR Checklist

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• [x] I have added example(s) inside the [./examples/] folder
• [x] I have added the example(s) to the integration test list for normal (~30 minutes) or long runner >30 minutes
• [x] I have checked the coding conventions as per the wiki
• [x] I have checked to ensure there aren't other open Pull Requests for the same update/change?

Description

This allows you to specify an AD group from a remote landing zone as part of the admin_groups block in the AKS module.

Original credit to @yanndb

Does this introduce a breaking change

• [ ] YES
• [x] NO

Testing

Run the example in compute/kubernetes_services/108-single-cluster-remote-adgroup-admin