[EKS] [request]: Increase/Customize reserved disk space on nodes

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**Tell us about your request**
Currently, the AWS managed nodegroup node images only reserve 1GB of local disk space for the OS/kubelet (configured in `/etc/kubernetes/kubelet/kubelet-config.json`). But the local operating system installation uses more than 2 GB. So even if ephemeral-storage resource requests/limits are configured adequately, a fully utilized node runs into Disk Pressure state.

AWS support asked me (Ticket 10768345041) to report the issue here.

**Which service(s) is this request for?**
EKS (managed nodegroup node image)

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
Managed Nodes cannot be customized easily to override that value (and IMHO it should be set to a good value from the start)

**Are you currently working around this issue?**
I configure slightly more ephemeral-storage resources that are actually needed on my workloads, but that increases waste and is not bullet-proof.

Start by reviewing the EKS managed nodegroup node image configuration at /etc/kubernetes/kubelet/kubelet-config.json and the reported Disk Pressure behavior. Done would require a supported way to increase or customize reserved disk space, or an improved default for managed nodegroup nodes.

Written by the indexing model from the issue text.