Add "planned" state to Purchase/Sale Packing Lists so that builders first build planned deliveries.
Then if there is no expected additional movement, the delivery is automatically moved to "confirmed".
This allows to support partial build that could come with global builders. Now builders will complete
only "planned" deliveries. This also solve the split of packing list when the same date was used,
the builder was updating current delivery. Now we can change packing list only in confirmed state
(not in planned state), therefore the builder will never add movement to the delivery the user is
changing.

This was adapted from seb commit to project repo. The difference is that here we do not confirm if
related movements belong to more then one root delivery value (packing list). This way we try to
handle the case of multiple split on the same date where the user first splits a packing list and
then splits again. In this case we want these splitted movements end up in the same packing list,
so the created packing list still has to be able to receive new movements, it is thus kept in
planned state. The user then hast to confirm this packing list manually.