Please check the 2 different attempts of refactoring on the following branches:

* extracting_order_controller: this was the first step, and it was the same for both approaches
* extracting_see_suggested_products: in this branch I tried to extract ProductsController before introducing the Upsell collaborator
* extracting_upsell: in this branch I tried to extract the Upsell collaborator before extracting ProductsController