Remove ProductModel tasks from Cookbook

[seif]

The class ProductModelTasks and IProductModelTasks in the cookbook just passes calls into the repository and returns entities.

Dont see the point of doing this, if what we want to show is simply binding for a CRUD app, then we should just use the Repository in the controller directly.

[sandord]

It might be wise to leave a remark that recommends delegating repository access to tasks as soon as the application (the audience is building based on the example) grows.

[cd21h]

Also migrate project to the Samples folder.