[crm] implementation planner

- Task: https://www.odoo.com/web/#id=8592&view_type=form&model=project.task&menu_id=3942&action=327
- Pad: https://pad.odoo.com/p/r.4BHh6hQdZ4GPR2qE
this will be replaced by the creation of plannerManager on the webclient object. Singleton is not needed anymore.