[IMP] column management in project / crm

- Task: https://www.odoo.com/web#id=8545&view_type=form&model=project.task&menu_id=3942&action=327
- Pad: https://pad.odoo.com/p/r.PJlXkLVOd4QZaxGR
Quite verbose and difficult to understand. Rename to default; selection values should be 'none': 'No specific behavior', 'copy': 'Copy to each new Project', 'link': 'Link to each new Project' .