Rename master to control plane - non-breaking changes only (#11394)

K8s is moving away from the "master" terminology, so kubespray should follow the same naming conventions. See 65d886bb30/sig-architecture/naming/recommendations/001-master-control-plane.md

roles/kubernetes/control-plane/tasks/pre-upgrade.yml

@@ -1,5 +1,5 @@
 ---
-- name: "Pre-upgrade | Delete master manifests if etcd secrets changed"
+- name: "Pre-upgrade | Delete control plane manifests if etcd secrets changed"
   file:
     path: "/etc/kubernetes/manifests/{{ item }}.manifest"
     state: absent
@@ -8,14 +8,14 @@
   register: kube_apiserver_manifest_replaced
   when: etcd_secret_changed | default(false)
 
-- name: "Pre-upgrade | Delete master containers forcefully"  # noqa no-handler
+- name: "Pre-upgrade | Delete control plane containers forcefully"  # noqa no-handler
   shell: "set -o pipefail && docker ps -af name=k8s_{{ item }}* -q | xargs --no-run-if-empty docker rm -f"
   args:
     executable: /bin/bash
   with_items:
     - ["kube-apiserver", "kube-controller-manager", "kube-scheduler"]
   when: kube_apiserver_manifest_replaced.changed
-  register: remove_master_container
+  register: remove_control_plane_container
   retries: 10
-  until: remove_master_container.rc == 0
+  until: remove_control_plane_container.rc == 0
   delay: 1