Use ArgoCD to deploy Cluster Addons instead of Terraform

[csantanapr]

Update the workshop deployment of EKS cluster to use ArgoCD to deploy cluster addons, currently its using terraform to create kubernetes manifests and helm charts and this is not a good practice since this can be done with GitOps, and ArgoCD is already deploy.

To have consistency with other projects like EKS Blueprints with GitOps we should use the gitops-bridge pattern to deploy cluster addons, the latest iteration of the pattern is used in the EKS Fleet Management workshop were the terraform/argocd integration code can be found in github.com/aws-samples/fleet-management-on-amazon-eks-workshop

The pattern can deploy argocd to spoke clusters, or the cluster addons can be deploy to spoke clusters from the hub without the need to have argocd install on the spoke clusters.
The gitops-bridge helm chart should be deployed in namespace per cluster using argocd appset in namespaces feature.