Create HCPs with externalDNS on AKS Clusters

User Story:

As a user of HyperShift on Azure, I want to be able to:

• create HCP with externalDNS setup on AKS clusters

so that I can achieve

• the ability to successfully setup HCPs on AKS for the ARO HCP effort.

Acceptance Criteria:

Description of criteria:

• Upstream documentation on setting up an HCP with externalDNS on AKS
• Any code changes needed to successfully setup HCP with externalDNS on AKS has been peer reviewed and approved

Out of Scope:

• Any private or publicPrivate topology setup.

Engineering Details:

• (optional) https://github/com/link.to.enhancement/
• (optional) https://issues.redhat.com/link.to.spike
• Engineering detail 1
• Engineering detail 2

This requires/does not require a design proposal.
This requires/does not require a feature gate.