Reorganizing the URLs seems to fix an issue with namespace collision in the URLs.
- URLs for product related operations are now in the /produits/ namespace ;
- Templates are now using a formalism of action_subject.html, which makes it simpler to find find them.
I've split everything in different concepts (groups, login, products and delivery) so that it's easier to find what we're looking for (the __init__.py file was really too big).