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/kubernetes-apps/external_provisioner/local_path_provisioner/tasks/main.yml

@@ -7,7 +7,7 @@
     group: root
     mode: 0755
   when:
-    - inventory_hostname == groups['kube-master'][0]
+    - inventory_hostname == groups['kube_control_plane'][0]
 
 - name: Local Path Provisioner | Create claim root dir
   file:
@@ -42,7 +42,7 @@
     dest: "{{ kube_config_dir }}/addons/local_path_provisioner/{{ item.file }}"
   with_items: "{{ local_path_provisioner_templates }}"
   register: local_path_provisioner_manifests
-  when: inventory_hostname == groups['kube-master'][0]
+  when: inventory_hostname == groups['kube_control_plane'][0]
 
 - name: Local Path Provisioner | Apply manifests
   kube:
@@ -53,4 +53,4 @@
     filename: "{{ kube_config_dir }}/addons/local_path_provisioner/{{ item.item.file }}"
     state: "latest"
   with_items: "{{ local_path_provisioner_manifests.results }}"
-  when: inventory_hostname == groups['kube-master'][0]
+  when: inventory_hostname == groups['kube_control_plane'][0]