0.15.0 Fix output: Rename "role_arn" output to "role_id"

what

• Fix output: Rename "role_arn" output to "role_id"

why

• Output role_arn was wrongly named, because it exposes "aws_iam_role.role.id" attribute
  instead of "aws_iam_role.role.arn".

• Added both role_arn and role_id