[REF] stock,mrp: make picking_type_id compute store in stock.move

In order to have always a picking_type_id on a stock move (and
consistent with his parent model), make it compute store.
Then clean the call of picking_type_id without change the behavior
(/!\ `move.picking_id.picking_type_id != move.picking_type_id` because
of mrp). Fix some test where the location(_dest) was unset in moves.

Also:
- Clean the mess in the create of `stock.picking` about that
and add a onchange to keep location(_dest) consistent with moves.
- The move `description_picking` is set when the `picking_type_id`
change, not only at the create method.

task-2373638