[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
awslabs/amazon-eks-ami#2446
awslabs/amazon-eks-ami#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.