Almost working test, Inventory API still does not process properly.

Had I not done that before? How did it worked? Weird. Maybe just changed the configuration on the Portal Type ?

I am unsure if they should not instead be in the delivery movement group, that way we might be able to discard my change to ERP5Site and get rid completely of this inventory movement thing.

Also: add `getTotalQuantity`. Why?

…and delete unused `z_catalog_stock_list_without_delete_for_inventory_virtual_movement`

In order to have Inventory Offset Lines, we want the user to be able to check
the generated lines before validating. This commit therefore adds an
intermediate state `planned`, which will be used to trigger generation of
Simulation Movements and building of the offset lines.

Some other small changes have been done to make the actions' names more clear
and adhere to ERP5 standards, but all keep backward compatiblity: previous states
have been kept, and previously validated inventories are now recorded so that
no Simulation Movements will be generated that would impact stock values.