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

roles/network_plugin/calico/templates/calicoctl.kdd.sh.j2

@@ -1,6 +1,6 @@
 #!/bin/bash
 DATASTORE_TYPE=kubernetes \
-{% if inventory_hostname in groups['kube-master'] %}
+{% if inventory_hostname in groups['kube_control_plane'] %}
 KUBECONFIG=/etc/kubernetes/admin.conf \
 {% else %}
 KUBECONFIG=/etc/cni/net.d/calico-kubeconfig \