How to accommodate external auth service with istio through mesh configuration with Azure DevOps

Can you please help me with below two queries? We need to add new changes to implement authorization policy in Istio gateway, This should be done during installation or upgrade of Istio via Azure DevOps pipeline.

To implement this via Azure Pipeline, we need some inputs to understand how can we accommodate below changes in our pipeline.

  1. How to accommodate external auth service with istio through mesh configuration with Azure DevOps yaml file(servicemesh yaml)?
  2. Apply Authorization Policy in istio-system namespace We have an YAML with ‘kind: AuthorizationPolicy’ for Istio. How can we call this file or apply this configuration during installation of Istio?