[IMP] stock: add picking partner_id

Add a related field to the partner_id of the picking. Note that
partner_id on stock.move is different from partner_id on stock.picking
in case of dropshipping, therefore we need to show both fields.

opw-656298

addons/stock/stock.py

@@ -1920,7 +1920,7 @@ class stock_move(osv.osv):
                                             auto_join=True, help="Location where the system will stock the finished products."),
 
         'partner_id': fields.many2one('res.partner', 'Destination Address ', states={'done': [('readonly', True)]}, help="Optional address where goods are to be delivered, specifically used for allotment"),
-
+        'picking_partner_id': fields.related('picking_id', 'partner_id', type='many2one', relation='res.partner', string='Transfer Destination Address'),
 
         'move_dest_id': fields.many2one('stock.move', 'Destination Move', help="Optional: next stock move when chaining them", select=True, copy=False),
         'move_orig_ids': fields.one2many('stock.move', 'move_dest_id', 'Original Move', help="Optional: previous stock move when chaining them", select=True),

addons/stock/stock_view.xml

@@ -1338,6 +1338,7 @@
                         <group name="destination_grp" string="Destination" groups="stock.group_locations">
                             <field name="location_dest_id" />
                             <field name="partner_id" context="{'contact_display':'partner'}" />
+                            <field name="picking_partner_id" context="{'contact_display':'partner'}"/>
                             <field name="move_dest_id" groups="base.group_no_one" readonly="1"/>
                         </group>
                         <group name="quants_grp" string="Reserved Quants" colspan="2" groups="base.group_no_one" attrs="{'invisible': [('state', '=', 'done')]}">