[EKS] [request]: configurable target group for kube service of type LoadBalancer

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**Tell us about your request**
The ability for a kube service object of type `LoadBalancer` to configure what nodes to add to target groups based upon a node selector. This would allow large shared clusters with multiple node groups/autoscaling groups to avoid having ALL nodes get added to a given target group.

**Which service(s) is this request for?**
EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
As long as we are using node ports for the connectivity between a load balancer created by a service of type `LoadBalancer` (see #981 for an alternative approach to today's host port solution) and the applications, all nodes within the kube cluster are getting added to the target group. This presents issues if there are multiple node groups/autoscaling groups within a given cluster (e.g. for segmentation or different workload types) as a given application likely does not run on all nodes.

Being able to define a node selector on the service for the target group to use could significantly cut down unnecessary target group membership and hence simplify reasoning about what network connectivity is available between a cluster and load balancers.

**Are you currently working around this issue?**
No

**Additional context**
N/A

**Attachments**
N/A

No implementation files or tests are named. Start by reviewing the requested Kubernetes Service type LoadBalancer behavior and related issue #981, then determine how a node selector should control target-group membership across EKS node groups. Done means the requested target-group selection behavior is defined and supported for the stated use case.

Written by the indexing model from the issue text.