Initial code for first draft of the cookbook

This is the first commit for https://github.com/ArcBees/GWTP/issues/321

I decided to create a GWTP Sample uniquely for unit-testing demo. I could have done this in the CarStore project, but this may have caused problems, because it would have been harder to keep the unit test cookbook in sync with the actual code.

I'm going to create a new page in the GWTP that will be home to the cookbook contents. I'm going to refer this GWTP-Samples project from the cookbook page.