Use the yaml callback plugin when running ansible-playbook

The default default Ansible screen output encodes and prints error outputs as a hard to read dense line of JSON.
This patch changes the ansible-playbook command behavior for this project to output yaml instead.

ansible.cfg

@@ -1,5 +1,6 @@
 [defaults]
 retry_files_enabled = False
+stdout_callback = yaml
 
 [connection]
 pipelining = True