Enable networkpolicy enforcement for nasa-veda hub

[yuvipanda]

With #4576, the nasa-veda cluster is a multi-tenant cluster with a public access component. We should enable network policy enforcement here.

Ref NASA-IMPACT/veda-jupyterhub#47 which tracks the overall issue.

Definition of done

• Network Policy enforcement is active on the nasa veda cluster
• There's some documentation on how this can be enabled for other clusters
• Only HTTP, HTTPS and DNS to the external internet is available on the Binder

Timeline

This needs to be fully complete before end of september, as that's the quarterly cadence for the VEDA project

[consideRatio]

Related tech issue in eksctl: eksctl-io/eksctl#7770, which is relevant following AWS announcement: https://aws.amazon.com/blogs/containers/amazon-vpc-cni-now-supports-kubernetes-network-policies/.

[yuvipanda]

I opened #4653 to track refinement of this issue.