wip: refactored working version

Refactorization: now ProductsList belong to the Pages and products are
distributed in pages Model wise.
Added ability for Page to setActive when clicking on it

This is helpful when you want to go to a page when clicking on the
edges.

Also removed unnecessary event triggers.
showing/hiding bullets on add/remove on collection
refactoring
Rendering without creating new views each time
Added 'id' to prods model & some drop behavior delimitation
Shifting products from pages when on drop.
Basics for lyout rendering
Added ability to change layouts on the fly