[MERGE] Improved search view UI

This branch is the result of a UI rethink of the search views.
In order to do that, many other parts had to be moved/reworked.
Main changes affect action manager, view manager and search view
(they have been almost completely rewritten)

Some highlights:
* search view has 3 submenus (filters, groupbys, favorites) and all inputs are included in these submenus
* view manager header is now responsive, and bootstrapized
* icons are now using fontawesome
* transitions between views should have much less flicker (because of work in action and view managers)
* debug mode has a pretty icon (because why not)
* we can now add custom groupbys (every groupable fields from the model are exposed (make sure you have good descriptive strings))