Yaml config file validation

[bruggerk]

Check that the config files are in the correct format.

Some quick google hits:

https://stuartgunter.wordpress.com/2011/05/25/yaml-and-the-importance-of-schema-validation/

http://tekiwiki.blogspot.com/2017/03/normal-0-false-false-false-en-us-x-none_15.html