Berks every time: Berkself POC

https://jira.opencrowbar.org/browse/CES-1562

This basic Berkshelf support runs at every call to the Chef-Solo jig.

* runs `berks init` on any cookbooks that don't have Berkshelf files
* runs `berks install` on any cookbooks that have a Berksfile.lock that has not been touched in more than 10 minutes.
* when berks install is run, if Rails.logger.level == 0, it dumps `berks shelf list`, and a list of cookbooks into the /var/log/crowbar/production.log for comparing what's available.