[IMP] remove sheet from the forms which are used for configuration and i...

...mproved some ugly views

- Task: https://www.odoo.com/web?#id=6091&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.VOFr7Zt1UDND0T3F