[IMP] Database Manager: Add a pg_dump binary flag for db export

- Task: https://www.odoo.com/web#id=8932&view_type=form&model=project.task&menu_id=3942&action=327
- Pad: https://pad.odoo.com/p/r.51queAunn0BulRwO
@rim-odoo,
replaced **kargs with **kwargs.