Replace another usage of map as a context for rendering by a proper view object, this time for rendering the products page

--HG--
rename : webapp/src/main/java/org/testinfected/petstore/helpers/ChoiceOfCreditCards.java => webapp/src/main/java/org/testinfected/petstore/views/ChoiceOfCreditCards.java
Replace yet more usages of map as rendering context,
this time for cart and order pages.