Merge testing harness into master

This currently has a pretty good 80+% coverage using chefspec 4/berkshelf 3 and work towards test-kitchen serverspec tests. This is far enough along to where it is worth merging this in master so we can pull it into COOK-3900 in parallel while we continue the serverspec tests. This will allow us to work on applying the changes to chefspec for apache 2.4 support on COOK-3900 and hopefully pull up the timeline on getting that released.