Update AKS gpu cluster setup

[anson627]

This pull request adds a new user guide for setting up an Azure AKS cluster with GPU nodes specifically for KubeRay, and updates references in the Kubernetes cluster setup documentation.

New Azure AKS GPU cluster setup guide:

• doc/source/cluster/kubernetes/user-guides/azure-aks-gpu-cluster.md: Added a detailed guide on creating an Azure AKS cluster with GPU nodes for KubeRay, including steps for creating a resource group, creating an AKS cluster, adding a GPU node group, and obtaining kubeconfig.

Documentation updates:

• doc/source/cluster/kubernetes/user-guides/k8s-cluster-setup.md: Added a reference to the new Azure AKS GPU cluster setup guide in the list of available cluster setup guides.
• doc/source/cluster/kubernetes/user-guides/k8s-cluster-setup.md: Updated the section for setting up an AKS cluster to include a reference to the new detailed setup guide.

Why are these changes needed?

Updated based on latest AKS public docs

Related issue number

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  make sure steps in quickstart run without issue on AKS cluster

[anson627]

@kevin85421 can you help to take a look at simple doc update?

[anson627]

@jcotant1 can you help to take a look?

[pcmoritz]

Thanks a lot for the contribution @anson627, can you fix the following high level points before we merge the PR?

1. Sign off on your commits so the DCO passes (https://github.com/ray-project/ray/pull/49992/checks?check_run_id=36079332073)
2. Put back the original links, that were in https://github.com/ray-project/ray/pull/49992/files#diff-4b96da3370400e06b8f96f19d13bfdeb122d56f179b4404ffbf501b17781cb48L30 to the top of the new documentation page to make it easier for people to follow and get more detailed information about the steps (or if applicable, you can mention the relevant docs in each step)

[anson627]

@pcmoritz @csivanich thanks for getting back to me! all comments addressed