[IMP] MRP : Made the manufacturing order (MO) number sequence same like ...

...sale order (SO)

- Task: https://www.odoo.com/web#id=8785&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.CWkkEKeRTtbGnXpu
Does not make sense to make it readonly?  Why could not the user change it?