[IMP] product : Remove UoM constraint from product module and give it in stock and account module.

Hello,

Task Link :
https://www.odoo.com/web#id=9119&view_type=form&model=project.task&action=327

Pad Link : 
https://pad.odoo.com/p/r.iiBJ1z8jL97d0qee

Thanks
rsi-odoo