[FL-34] Use custom CNI for cluster create operation

[jiayiwang7]

Currently, EKS-A supports replacing the default CNI with custom option through cluster upgrade: https://anywhere.eks.amazonaws.com/docs/clustermgmt/networking/cluster-replace-cilium/

It would be nice to be able to specify the custom CNI during cluster creation so that user does not need to manually swap it after cluster is created.

[Cajga]

This would be awesome. It would be also nice to keep in mind that some custom CNI (like Cilium) requires to have a cluster without kube-proxy to be able to utilize some of it's features. I've opened a separate ticket regarding this request.