Replace kube-master with kube_control_plane (#7256)

This replaces kube-master with kube_control_plane because of [1]:

  The Kubernetes project is moving away from wording that is
  considered offensive. A new working group WG Naming was created
  to track this work, and the word "master" was declared as offensive.
  A proposal was formalized for replacing the word "master" with
  "control plane". This means it should be removed from source code,
  documentation, and user-facing configuration from Kubernetes and
  its sub-projects.

NOTE: The reason why this changes it to kube_control_plane not
      kube-control-plane is for valid group names on ansible.

[1]: https://github.com/kubernetes/enhancements/blob/master/keps/sig-cluster-lifecycle/kubeadm/2067-rename-master-label-taint/README.md#motivation

contrib/terraform/aws/modules/iam/main.tf

@@ -1,6 +1,6 @@
 #Add AWS Roles for Kubernetes
 
-resource "aws_iam_role" "kube-master" {
+resource "aws_iam_role" "kube_control_plane" {
   name = "kubernetes-${var.aws_cluster_name}-master"
 
   assume_role_policy = <<EOF
@@ -40,9 +40,9 @@ EOF
 
 #Add AWS Policies for Kubernetes
 
-resource "aws_iam_role_policy" "kube-master" {
+resource "aws_iam_role_policy" "kube_control_plane" {
   name = "kubernetes-${var.aws_cluster_name}-master"
-  role = aws_iam_role.kube-master.id
+  role = aws_iam_role.kube_control_plane.id
 
   policy = <<EOF
 {
@@ -130,9 +130,9 @@ EOF
 
 #Create AWS Instance Profiles
 
-resource "aws_iam_instance_profile" "kube-master" {
+resource "aws_iam_instance_profile" "kube_control_plane" {
   name = "kube_${var.aws_cluster_name}_master_profile"
-  role = aws_iam_role.kube-master.name
+  role = aws_iam_role.kube_control_plane.name
 }
 
 resource "aws_iam_instance_profile" "kube-worker" {