Clarify layouts

[paulandrieux]

At this time we have this layout hierarchy:

                          base
                    layout ┴
    ajaxModalLayout   ┴   backendLayout    
modal   ┴

1. I think "base" and "layout" could be merged
2. "base" should not initalize angular because it has "backendLayout" in it's hierarchy and the backend has no need of angular.
3. Victoire should come with a "frontendLayout" that initialize angular
4. Victoire should not come with a backendLayout because it's relative do specific business logic

Please consider a layout hierarchy like:

                  baseLayout 
    ajaxModalLayout   ┴   frontendLayout    
modal   ┴