Reference service for target group binding in a different namespace

[lumoVWGS]

Is your feature request related to a problem?
As the loadbalancer controller's settings only allow the watch exact one OR all namespaces there can be the following situation:

We normally want to restrict the one watched namespace to our infrastructure namespaces, to avoid developers to be able to deploy ressources in their namespaces that create AWS ressources. But we still would like to have the possibility to create TargetGroupBindings for services that are outside of our infrastructure namespace - without the targetgroupbinding k8s ressource being outside of our infra namespace.
However, this is currently not possible as the kube api needs a namespace when getting requested for services - however a namespace is not configurable in the serviceRef so far:
https://kubernetes-sigs.github.io/aws-load-balancer-controller/latest/guide/targetgroupbinding/spec/#elbv2.k8s.aws/v1beta1.ServiceReference

Describe the solution you'd like
A namespace can be added to the serviceRef and the controller can handle TargetGroupBindings that reference services in another namespace.

Describe alternatives you've considered
Alternatively it would work if the loadbalancer controller can be configured to watch more than one namespace (but not all).

[M00nF1sh]

@lumoVWGS
We can change the controller to support watch multiple namespaces(shall be simple with the recent controller-runtime changes).
But i'm not sure how this can address your request of binding to a different namespace.