[REV] manufacturing: restore subcontracting page

This reverts commit 18e9a66f18.
It was removed in 12.0 but must be kept in 13.0

manufacturing/management/subcontracting.rst

@@ -0,0 +1,107 @@
+Subcontract the manufacturing of some products 
+==============================================
+
+Some business subcontract the production of some finished products
+through subcontractors. This can be easily managed through Odoo.
+
+Configuration
+-------------
+
+Go in the :menuselection:`Manufacturing --> Configuration --> Settings` and tick the box *Subcontracting*.
+
+.. image:: media/subcontracting01.png
+    :align: center
+
+You can now define subcontractors contacts. When you purchase or receive
+products from a contact of type subcontractor, the correct stock moves
+are created to represent the subcontracting of the production.
+
+.. image:: media/subcontracting02.png
+    :align: center
+
+The next step is to create a Bill of Material of type *subcontracted*.
+In this BoM, list the components you need to supply to the
+subcontractor.
+
+.. image:: media/subcontracting03.png
+    :align: center
+
+You can also define subcontractors on the BoM.
+
+-  If no subcontractor is set, the BoM can be used by any subcontractor
+
+-  If some are set, the BoM can only be used for those subcontractors
+
+.. image:: media/subcontracting04.png
+    :align: center
+
+The configuration part is already done!
+
+Receive or buy a subcontracted product
+--------------------------------------
+
+You have two options to trigger a the subcontracting of a product:
+
+-  Option A: You can buy the subcontracted product from your
+       subcontractor
+
+-  Option B: You can directly receive the subcontracted product
+
+Let’s start with option A (option B is just a simpler version of it).
+
+Create a new purchase order. The vendor must be a subcontractor. The
+unit price should be the cost you are paying to the subcontractor for
+the subcontracting (it’s thus not necessarily the total cost of the
+subcontracted product).
+
+.. image:: media/subcontracting05.png
+    :align: center
+
+The validation of the purchase order creates automatically the receipt.
+Whenever you receive the product, you can validate the receipt. The
+following stock moves are created:
+
+-  For the components
+
+    From Subcontracting To Production
+
+-  For the subcontracted product
+
+    From Production to Subcontracting
+
+    From Subcontracting to Stock
+
+The *Subcontracting Location* represents the place where the products
+are at your subcontractor’s warehouse. It is configured as an internal
+location, the components that are sent to the subcontractor are still
+valued in your stock.
+
+For option B, you simply can create the receipt manually with a partner
+of type subcontractor defined on it.
+
+Resupply the subcontractor with the components
+----------------------------------------------
+
+There are 3 ways to manage the resupply of your subcontractor with the
+components:
+
+-  Manually. You simply create a delivery order on which you set the
+       subcontractor as partner and you choose the components to deliver
+
+.. image:: media/subcontracting06.png
+    :align: center
+
+-  With reordering rules. You can define a reordering rule on the
+       Subcontracting location to ensure that they are always enough
+       components send to your subcontractors.
+
+.. image:: media/subcontracting07.png
+    :align: center
+
+-  On order. You can also deliver the components to your subcontractors
+       each time you order a subcontracted product. For this, you need
+       to tick the route “Resupply Subcontractor on Order” on the
+       components concerned.
+
+.. image:: media/subcontracting08.png
+    :align: center