[FIX] mrp: correct Raw Materials Location

- Create a BOM with a rounting
- On the routing, set a location
- Create a MO with the BOM

The 'Raw Materials Location' is set on the location on the picking type
although in practice, the location of the routing will be used:

https://github.com/odoo/odoo/blob/f65bdd17308d6fa5f984dd23f0b345cd92c977cb/addons/mrp/models/mrp_production.py#L457-L460



This is confusing for end users.

We improve the onchange mechanism to set the location which will be
used. We also rename 'Production Location' since it is confusing for the
users.

opw-2116760

closes odoo/odoo#39647

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>