Move TK driver config into actual driver section
Use more YAML-y YAML for TK config

Don’t mix Ruby-like structures w/ native YAML
Update for Serverspec v2
Convert content assertions to current syntax
Correct expectation in namenode spec
Use Supermarket for Berkshelf
Allow `deploy` to act as mapred user for deploys

Courtesy of the deployment config written for contacts_hadoop,
this allows Hadoop jobs to be deployed without granting too much
in the way of sudoers.
Bump to v2.3.0