Add framework for configuring Chef recipes.

 - Chef cookbooks may be placed in config/chef/cookbooks.
 - Recipes provisioned using fabric-provision (http://fabric-provision.readthedocs.org/en/latest/).
 - Recipes can be provisioned one at a time from the command line by specifing fabric operation install_chef_recipes, all at once by setting target=chef_recipes, or as part of a full install (default). This mirrors closely 'custom' install operations.
 - Fabric properties are added to Chef's node environment, extra node properties can be added to config/node_extra.json (or flavor variant of this file). chef version of fabric properties are prefixed with cloudbiolinux_.