New Breadcrumb mechanism!

This new Breadcrumb is almost automatic, except in special cases. These cases can be resolved via the `Change:UpdateBreadcrumb` event. See `directives/breadcrumb.js` and examples are in Website and Catalog (`admin.js` files).

**There are still a few things to be done:**
- remove all `<rbs-workspace-config>` (and child elements) in Twig templates.
- remove useless `RbsChange.Breadcrumb` service (and all its references in controllers, directives, ...).
- fixed hard-coded labels (in english for the moment, search for **FIXME i18n** to find them).