Update eks and vpc module versions (breaking changes)

[ankitm123]

Summary

We should update the eks module version to the latest, and check what are the issues we have.
There are quite a few breaking changes (including removal of map_roles and launch templates)
https://github.com/terraform-aws-modules/terraform-aws-eks/releases/tag/v18.0.0

[msvticket]

An attempt at an inventory of things we need to do to preserve the existing functionality of the cluster module when updating the eks module (using https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/docs/UPGRADE-18.0.md as reference):

• manage aws-auth configmap ourselves
• configure kubeconfig (probably needed for the above)
• rename and change use of
  • node_groups -> eks_managed_node_groups
  • worker_groups -> self_managed_node_groups
• 'To use the legacy (< 18.x) resource naming convention, set prefix_separator to "".'

We should use the techniques described in https://developer.hashicorp.com/terraform/language/modules/develop/refactoring to make the upgrade smooth for our users.

[msvticket]

More information here terraform-aws-modules/terraform-aws-eks#1744 (comment)