Replace az aks get-credentials with GH action logins

[adamrushuk]

Replace az aks get-credentials with the following GitHub Actions:

• azure/setup-kubectl@v3
• azure/use-kubelogin@v1
• azure/aks-set-context@v3

See example here: https://medium.com/microsoftazure/safely-access-azure-kubernetes-service-in-github-action-with-aad-federated-identity-b4ab39721a20