[EKS] [fargate]: Allow custom node labels in eks fargate instances

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**Tell us about your request**
What do you want us to build?
I would like to add custom node labels to eks fargate nodes
**Which service(s) is this request for?**
This could be Fargate, EKS,

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**

In our scenario, we have some pods that are scheduled with specific node selector policy. We are using mutating webhooks to apply this nodeselector annotations in our pods. AFAIK, there is no option to add custom node labels to eks fargate nodes.
These are the default labels :+1:
```
beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,eks.amazonaws.com/compute-type=fargate,failure-domain.beta.kubernetes.io/region=eu-central-1,failure-domain.beta.kubernetes.io/zone=eu-central-1a,kubernetes.io/arch=amd64,kubernetes.io/hostname=ip-10-253-45-6.eu-central-1.compute.internal,kubernetes.io/os=linux,topology.kubernetes.io/region=eu-central-1,topology.kubernetes.io/zone=eu-central-1a
```
and I would like to add my custom ones, to allow mutation webhooks work in our scenario.

**Are you currently working around this issue?**

It is something that we can't control.

The issue names EKS Fargate and describes the default node labels and node-selector/webhook use case, but mentions no repository files, tests, or entry points. Start by locating the EKS Fargate configuration and existing label handling; done means a supported way to provide custom node labels that enables the described selectors.

Written by the indexing model from the issue text.