[EKS] [request]: enforce authentication for /version

### Community Note

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**Tell us about your request**

The unauthenticated `/version` endpoint on the Kubernetes API exposes a lot of information about the cluster:

```
{
"major": "1",
"minor": "19+",
"gitVersion": "v1.19.6-eks-49a6c0",
"gitCommit": "49a6c0bf091506e7bafcdb1b142351b69363355a",
"gitTreeState": "clean",
"buildDate": "2020-12-23T22:10:21Z",
"goVersion": "go1.15.5",
"compiler": "gc",
"platform": "linux/amd64"
}
```

When public access is enabled, this lets anyone gleam information about the cluster that could be useful to an attacker (knowing the k8s version for example) or the fact that it's a k8s cluster in the first place.

It seems unnecessary to publish this much information without requiring authentication. The primary reason I can imagine for this is to make `kubectl version` work, but my expectation would be that it's able to use the authentication information provided in the kubeconfig context to do that request (since `version` is dependent on the active context).

**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?**

I'd like to not have a bunch of information about my cluster available to the public, even though I'd like public API access available to make developer's lives more convenient (and as such set the API IP whitelist to `0.0.0.0/0`).

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

No, though there's been discussions about forcing stuff through a proxy/VPN and disabling public access in order to mitigate the metadata leak.

Start by reviewing the unauthenticated Kubernetes API /version endpoint and how kubectl version uses authentication from the active kubeconfig context. Done means public EKS API access no longer exposes /version without authentication while authenticated kubectl version requests continue to work.

Written by the indexing model from the issue text.