Move config.cfg to the config/ dir

This PR simply moves littlechef's config.cfg file into the config/ directory. It also updates the init and setup steps, as well as the error message for a missing config file to reflect this. It builds and works as expected.

Putting config files (be they littlechef's or chef-solo's) under the config/ dir in a kitchen makes sense to new users, while having 2 'config*' files (one the .cfg, the other a dir) in the root of a kitchen is a little confusing.