Revert removing output asg_iam_role_name

And rework its implementation following current policy attaching style.

Author: Magicloud

modules/single-node-asg/outputs.tf

@@ -2,3 +2,8 @@ output "asg_name" {
   value       = module.server.name
   description = "`name` exported from the Server `aws_autoscaling_group`"
 }
+
+output "asg_iam_role_name" {
+  value       = module.instance_profile.iam_role_name
+  description = "`name` exported from the Service Data `aws_iam_role`"
+}