Switch to using Librarian-chef instead of Berkshelf

Berkshelf vs Librarian:

* Berkshelf can use a cookbook metadata to resolve dependencies.
* Berkshelf is transparent to the project's file structure. It doesn't
  require to install everything into ./cookbooks/ and use ./tmp/ for caching.

* Librarian-chef doesn't have tons of dependencies, with some who require C
  extensions.
* Librarien-chef actually respects it's .lock file.

So Berkshelf is better for building cookbooks and Librarian-chef to manage
project repos.