Change isPageType() function to reflect Product Opener evolution

[CharlesNepote]

What

• Change isPageType() function to reflect Product Opener evolution
• openfoodfacts/openfoodfacts-server@71b4d49

Example:
if ($(".products")[0]) return "list";
will become
if ($(".list_of_products_page")[0]) return "list";

[svensven]

i did at least some of the types in 9e90397, albeit a different way