feat: Added the varaible create_policy to allow users to create their own policy

[markoskandylis]

What does this PR do?

This is an enchantment, Adding the create_policy variable to allow users to create and use their own policies. A faction already exists in addon module.

🛑 Please open an issue first to discuss any significant work and flesh out details/direction - we would hate for your time to be wasted.
Consult the CONTRIBUTING guide for submitting pull-requests.

Added the variable create_policy (true or false) for the following modules:
aws_efs_csi_driver
aws_for_fluentbit
aws_fsx_csi_driver
aws_privateca_issuer
aws_load_balancer_controller
aws_gateway_api_controller
cluster_proportional_autoscaler
external_secrets
velero

This will allow the users to attach their own policy without creating the preexisting one

Motivation

I want to have the ability to allow the module to create the role but create my own policy
example usage:

module "eks_blueprints_addons" {
  source  = "aws-ia/eks-blueprints-addons/aws"
  version = "~> 1.16"

  cluster_name      = module.eks.cluster_name
  cluster_endpoint  = module.eks.cluster_endpoint
  cluster_version   = module.eks.cluster_version
  oidc_provider_arn = module.eks.oidc_provider_arn

  # Using GitOps Bridge
  create_kubernetes_resources = false

  external_secrets = {
    create_policy = false
    role_policies = {
      external_secreat_policy = aws_iam_policy.external_secrets_irsa_policy.arn
    }
  }

  # EKS Blueprints Addons
  enable_cert_manager                 = local.aws_addons.enable_cert_manager
  enable_aws_efs_csi_driver           = local.aws_addons.enable_aws_efs_csi_driver
  enable_aws_fsx_csi_driver           = local.aws_addons.enable_aws_fsx_csi_driver
  enable_aws_cloudwatch_metrics       = local.aws_addons.enable_aws_cloudwatch_metrics
  enable_aws_privateca_issuer         = local.aws_addons.enable_aws_privateca_issuer
  enable_cluster_autoscaler           = local.aws_addons.enable_cluster_autoscaler
  enable_external_dns                 = local.aws_addons.enable_external_dns
  enable_external_secrets             = local.aws_addons.enable_external_secrets
  enable_aws_load_balancer_controller = local.aws_addons.enable_aws_load_balancer_controller
  enable_fargate_fluentbit            = local.aws_addons.enable_fargate_fluentbit
  enable_aws_for_fluentbit            = local.aws_addons.enable_aws_for_fluentbit
  enable_aws_node_termination_handler = local.aws_addons.enable_aws_node_termination_handler
  enable_karpenter                    = local.aws_addons.enable_karpenter
  enable_velero                       = local.aws_addons.enable_velero
  enable_aws_gateway_api_controller   = local.aws_addons.enable_aws_gateway_api_controller

  tags = local.tags
}

• Resolves Add the create_policy variable to allow users attach their own policy #394

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I ran pre-commit run -a with this PR

For Moderators

• [] E2E Test successfully complete before merge?

Additional Notes

[bryantbiggs]

see #394 (comment)