Add chef-vault support for the application data bag

This adds an extra attribute: chef_vault, which if set to true, uses
chef-vault (https://github.com/Nordstrom/chef-vault) rather than data_bag_item
in order to load the supermarket data, allowing it to be encrypted on the chef
server.
Bump cookbook version
Merge branch 'mh/chef-vault'

Conflicts:
	metadata.rb