[2.x][AKS] Allow user specified loadbalancer annotations

[michasHL]

After updating to 2.x I don't see a way to customize the generated k8s service per HTTPGateway in the way it could work with our AKS standard load balancer setup.

Before we're able to add custom annotations into the helm values file that got applied to the service directly.
After the change, the service seems to be created based on the HTTPGateway resource with no way of providing the required annotations:

NGF spec: https://docs.nginx.com/nginx-gateway-fabric/reference/api/#gateway.nginx.org%2fv1alpha2.ServiceSpec
AKS load balancer service annotations: https://learn.microsoft.com/en-us/azure/aks/load-balancer-standard#customizations-via-kubernetes-annotations

I would like to understand what I could do to make this work with our current setup of requiring the annotations to be set for an external IP to be bound.
I think I can follow the code good enough to contribute this change myself but of course it might require an addition to the service spec referenced above.

[bjee19]

Hey @michasHL, please refer to this document on setting annotations on the generated k8s service.

This has been a little confusing and other users have also struggled in finding how to set these annotations/labels, but following the sig gateway-api's guidelines using the infrastructure field on the Gateway is the way we do it.

[michasHL]

Awesome. Thanks I will try this out.