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/tokens/tasks/gen_tokens.yml

@@ -5,7 +5,7 @@
     dest: "{{ kube_script_dir }}/kube-gen-token.sh"
     mode: 0700
   run_once: yes
-  delegate_to: "{{ groups['kube-master'][0] }}"
+  delegate_to: "{{ groups['kube_control_plane'][0] }}"
   when: gen_tokens|default(false)
 
 - name: Gen_tokens | generate tokens for master components
@@ -14,11 +14,11 @@
     TOKEN_DIR: "{{ kube_token_dir }}"
   with_nested:
     - [ "system:kubectl" ]
-    - "{{ groups['kube-master'] }}"
+    - "{{ groups['kube_control_plane'] }}"
   register: gentoken_master
   changed_when: "'Added' in gentoken_master.stdout"
   run_once: yes
-  delegate_to: "{{ groups['kube-master'][0] }}"
+  delegate_to: "{{ groups['kube_control_plane'][0] }}"
   when: gen_tokens|default(false)
 
 - name: Gen_tokens | generate tokens for node components
@@ -31,14 +31,14 @@
   register: gentoken_node
   changed_when: "'Added' in gentoken_node.stdout"
   run_once: yes
-  delegate_to: "{{ groups['kube-master'][0] }}"
+  delegate_to: "{{ groups['kube_control_plane'][0] }}"
   when: gen_tokens|default(false)
 
 - name: Gen_tokens | Get list of tokens from first master
   command: "find {{ kube_token_dir }} -maxdepth 1 -type f"
   register: tokens_list
   check_mode: no
-  delegate_to: "{{ groups['kube-master'][0] }}"
+  delegate_to: "{{ groups['kube_control_plane'][0] }}"
   run_once: true
   when: sync_tokens|default(false)
 
@@ -49,7 +49,7 @@
     executable: /bin/bash
   register: tokens_data
   check_mode: no
-  delegate_to: "{{ groups['kube-master'][0] }}"
+  delegate_to: "{{ groups['kube_control_plane'][0] }}"
   run_once: true
   when: sync_tokens|default(false)
 
@@ -58,7 +58,7 @@
   args:
     executable: /bin/bash
   when:
-    - inventory_hostname in groups['kube-master']
+    - inventory_hostname in groups['kube_control_plane']
     - sync_tokens|default(false)
-    - inventory_hostname != groups['kube-master'][0]
+    - inventory_hostname != groups['kube_control_plane'][0]
     - tokens_data.stdout