Azure AKS UI should be simplified

### Describe what's missing in our docs

In [this section](https://kestra.io/docs/installation/kubernetes-azure-aks#access-kestra-ui) we tell the end user that they must deploy an Azure Application Gateway in order to configure access to the UI.

This is not user-friendly as the configuration for an Application Gateway is quite complex. I would propose dropping this as for users coming to Kestra on AKS for the first time it would be easier to suggest deploying either a load balancer directly on the cluster or to just port-forward.

E.g. load balancer
```
# Create the file
cat << EOF >> loadbalancer.yaml
apiVersion: v1
kind: Service
metadata:
name: kestra-webserver
spec:
selector:
app.kubernetes.io/component: webserver
ports:
- protocol: TCP
port: 80 # This is the port exposed by the service (you can change it if needed)
targetPort: 8080 # This is the port your web server is listening on inside the pod
type: LoadBalancer # This exposes the service externally via a cloud LoadBalancer
EOF

# create the service
kubectl apply -f loadbalancer.yaml
```

Start with the “Access Kestra UI” section in the Azure AKS installation documentation linked in the issue. Review the existing Application Gateway guidance and the proposed LoadBalancer and port-forward alternatives, then update the section so the simpler access options are documented and verify the YAML and kubectl commands are accurate.

Written by the indexing model from the issue text.