[Feature] Built-in Policy for Unique Ingress Host

**Is your feature request related to a problem? Please describe.**
Team operates a multitenant kubernetes clusters, and this would help prevent any conflicts between applications who externalizing service within our cluster. The annotation "metadata.gatekeeper.sh/requires-sync-data" is only supported by Built-in Policies as per documentation.

**Describe the solution you'd like**
Create a Built-in Policy that support UniqueIngressHost.

Link to built-in policies.
https://learn.microsoft.com/en-us/azure/aks/policy-reference

Link to template
https://open-policy-agent.github.io/gatekeeper-library/website/validation/uniqueingresshost/