Output the role names and pass them to other modules

[bhavikkumar]

Currently a module know what the roles are that are being created. Instead the names should be passed in to the module as a variable.

For example currently principals in the terraform-state module are defined as:

 "arn:aws:iam::${var.account_id}:role/OrganizationAccountAccessRole",
 "arn:aws:iam::${var.account_id}:role/Admin",
 "arn:aws:iam::${var.account_id}:role/Terraform",

Instead this could be achieved by a list variable and the following block:

"${formatlist("arn:aws:iam::%s:role%s", var.account_id, var.role_names)}"