Enable Pod Identity addons by default

[g-iannelli]

Is your feature request related to a problem? Please describe.
Currently, Pod Identity is not included as a default addon when provisioning EKS clusters. The module's components (EBS CSI driver, AWS Load Balancer Controller, Cluster Autoscaler) still rely on IRSA (IAM Roles for Service Accounts), which requires OIDC provider configuration and is more complex to manage. This leads to additional setup overhead and prevents adoption of AWS's newer, recommended authentication method.

Describe the solution you'd like
Include EKS Pod Identity as a pre-configured addon in the eks-addons module and migrate all existing IAM-based components from IRSA to Pod Identity. The solution should:

• Enable the EKS Pod Identity addon by default in the modules/eks-addons Terraform module
• Migrate the following components from IRSA to Pod Identity:
  • EBS CSI driver (modules/iam-for-ebs-csi-driver)
  • AWS Load Balancer Controller (modules/iam-for-load-balancer-controller and katalog/load-balancer-controller)
  • Cluster Autoscaler (modules/iam-for-cluster-autoscaler and katalog/cluster-autoscaler)
  • AWS Node Termination Handler (katalog/node-termination-handler)
• Update Terraform modules to create Pod Identity associations instead of IRSA trust policies
• Update Kubernetes manifests to remove service account annotations and use Pod Identity
• Provide configuration options to disable Pod Identity if needed for backwards compatibility
• Include migration documentation for existing clusters
• Ensure proper IAM permissions are configured for the addon

Additional context
EKS Pod Identity has been AWS's recommended approach for workload authentication since 2023. Migrating to it would:

• Align the module with AWS best practices
• Simplify IAM configuration (no OIDC provider needed)
• Reduce complexity in Terraform modules and Kubernetes manifests
• Improve security posture with simpler permission models
• Reduce technical debt across all module components

Consider providing a feature flag for backwards compatibility and a clear migration path for users with existing clusters using IRSA.