Fix ansible-lint error 502 (unnamed-task) for example playbooks.

This patch adds 'name' to all example playbook tasks that did not
have it, fixing ansible-lint's error 'unnamed-task'.

playbooks/host/hosts-present-with-managedby_host.yml

@@ -4,7 +4,8 @@
   become: true
 
   tasks:
-  - ipahost:
+  - name: Ensure hosts are present with managedby_host attribute.
+    ipahost:
       ipaadmin_password: SomeADMINpassword
       hosts:
       - name: host01.example.com