feat(cockpit/dateFilter): add date filter on process definition view

This commit adds a new filter to the process definition view: Start Date
Filter. This start date filter enables the possibility to filter after
process instances which have been start "after" or "before" a specific
date (the combination of both represents "between" two dates).

related to CAM-1613
improve(cockpit): refactoring of the page title and breadcrumbs

This commit also improve the handling of user task groups input:
 - prevent submission when the field is left empty
 - prevent submission when a group is already present

Related to CAM-1779, CAM-1182
refactor(cockpit/styles): generate CSS from Less

Also allows to easily change the color and logos of header.

Closes CAM-1780
fix(grunt): add target to the build task in auto-build
chore(engine/REST): create subresource for historic process instance

related to CAM-1852
chore(cockpit): remove unnecessary params from controller