[IMP] purchase,stock: edit PO line quantity

This commit adapt purchase to be able to edit purchase line ordered quantity
and propagate it to the related picking after the request for quotation
validation.

These are the supported use case

- When you increase the quantity on a purchase line, an extra move (and
an extra picking if they are all done or canceled) is created with the
difference between old and new value and the push rules are applied on
it.

- When you decrease the quantity of a purchase line, different behaviors
can occurs:
  * If you plan to decrese the ordered quantity under the received
    quantity, you get a user error saying tht you have to make some
    return before.
  * Else the moves not done or cancelled are decreased by starting with
    move having no procurement_id. The decrease is not propagated
    through push or pull rules.
  * If you decreased the quantity under the invoiced quantity, a next
    activity is created to remind you to do a refund.

0 files changed, 0 insertions, 0 deletions