Move recover_control_plane/master to control-plane (#7236)

According to the following recommendation, this moves the directory
to control-plane:

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".

recover-control-plane.yml

@@ -15,7 +15,7 @@
 
 - hosts: "{{ groups['kube-master'] | first }}"
   roles:
-    - { role: recover_control_plane/master }
+    - { role: recover_control_plane/control-plane }
 
 - include: cluster.yml