Updated berkshelf to 3.1.5, chefspec to 4.0.0 and foodcritic to 4.0

* Updated berkshelf from 2.0.18 to 3.1.5 in Gemfile
* added supermarket source to Berksfile
* some refactoring of the Berksfile
* removed Gemfile.lock since its not supposed to be in master branches
* also updated chefspec to 4 and foodcritic to 4 (like done some time ago for the other cookbooks)

Change-Id: I787912448337040ccf26a1126d848c76e7148caf
Implements: blueprint update-berkshelf