[Feature] Support for new args for nodeadm

[inesshz]

What feature/behavior/change do you want?

I am trying to use these new features provided here : using expression for max pods and using proxies for nodeadm https://github.com/awslabs/amazon-eks-ami/pull/2446 https://github.com/awslabs/amazon-eks-ami/pull/2384

Why do you want this feature?

I am trying to use these two new features for our clusters via eksctl but this is not being applied. I believe eksctl doesnt support these arguments in the nodeadm spec yet.