aks cluster create with predefined public ip for AGIC

It feels like the `ak cluster create` command is missing a command argument to specify the predefined Public IP address resource, just like we can by using the `--load-balancer-outbound-ip-prefixes` or `--load-balancer-outbound-ips`.

I could use the [Greenfield approach](https://docs.microsoft.com/en-us/azure/application-gateway/tutorial-ingress-controller-add-on-new) with such arguments, as I have the need to use prefined/existing Public IP address resources. No I have to revert to the [Brownfield approach](https://docs.microsoft.com/en-us/azure/application-gateway/tutorial-ingress-controller-add-on-existing#enable-the-agic-add-on-in-existing-aks-cluster-through-azure-cli).

Maybe extend the command with a `--appgw-inbound-ips` and `--appgw-inbound-ip-prefixes` ?

p.s. side question, is the `--zones {1, 2, 3}` input on the AKS cluster being forward to the AGIC in case of using `--appgw-name`?

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#### Document Details

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* ID: d75c3a8d-1187-bea1-a7d4-7ebba71c1790
* Version Independent ID: 75b0c352-762e-16ae-5cc6-d807ffc1dc3f
* Content: [az aks](https://docs.microsoft.com/en-us/cli/azure/aks?view=azure-cli-latest#az_aks_create)
* Content Source: [latest/docs-ref-autogen/aks.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/master/latest/docs-ref-autogen/aks.yml)
* Service: **container-service**
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**