This was somehow overlooked, but it should work.
This needs to change how the InventoryMutateForm handles quantities, as
the amount has to be split from the metric for addition to work.
This finally makes the licensing under AGPL-3.0-or-later explicit after
I got the okay from the kickstart source owners.
This also checks the REUSE compliance in a pre commit hook, and
therefore also in CI.
This also does a major restructuring of the inventory mutate form.
Some things still are not as they should be, but it mostly works like
before. They can be fixed later.
Co-authored-by: Theo Reichert <theo.reichert@mailbox.tu-dresden.de>