Odoo13 新功能：委外

[ADD] mrp_subcontracting

In a few words, it allows to send components to a subcontractor partner
and receive a finished product. The production is managed through classical
manufacturing orders where the raw and finished location is the
subcontracting location. When creating a receipt picking for a
subcontractor partner, the location_id of the moves will be set to the
subcontracting locations by using the property_stock_customer and
property_stock_supplier of the partner. An override of _action_confirm
will create the manufacturing order.

When a subcontracted bom contains tracking, the produce wizard is
available from the picking to record which lots were produced/consumed.

New type on the BoM: subcontract
New type on res.partner: subcontactor
New location per company (we still own the components stored at the
subcontractor so they're still valued)
New routes created to resupply the subcontracting location on order or
not (through a reordering rule).
Override of res.partner to set the property_stock_customer/supplier on
subcontactor partners.

Proper tests were added too.

Joint work with: Arnaud Baes arb@odoo.com

task 1831382