[EXAMPLE] - Enhancements for full-private-eks cluster

[askulkarni2]

1. Refactor example so it looks like our other examples
2. Make it work with CI testing
3. Example on setting up on-prem via VPN, DC, TGW

[github-actions]

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[lindarr915]

Terraform examples of provisioning AWS Load Balancer Controller in a fully private EKS Cluster is desired for me