Set output cost in done transition
For now, the output cost is set when the moves are created (explode bom or update), but this is based only the cost of the input moves.
There are other costs like the one from the works (or outsourcing) and in this case the user must manually set the extra cost which is not very friendly.
I propose to set the cost if it is not valid (and if there is a unique product) during the done transition. This way it is always the full cost that is applied.