Generate Policyfiles on the fly

[tas50]

👻 Brief Description

Right now to test a cookbook with Test Kitchen you need either a Berksfile or a Policyfile. These need to be included just for depsolving in test. We can make this happen automatically with a bit of work, which would make using Test Kitchen easier and reduce boilerplate code in cookbooks, which is always a good thing.

Scenarios:

Berksfile in the cookbook

Do what we've always done. Use that berksfile for depsolving

Policyfile in the cookbook

Do what we've always done. Use that Policyfile for depsolving

No Berksfile or Policyfile

Magic starts! Generate a policyfile that includes everything in test/cookbooks and includes the run_list specified in the kitchen.yml config. This lets a user just specify a run_list in the kitchen.yml and have it work with the included test cookbook without additional work or boilerplate code.