Add employee on shipments for some states
Some transitions on shipment are quite important, for example the packing of outgoing shipment. It will be good to know which employee did it.
Also such new fields could be used for assignation of the transition like needed for #6180. It would also be used for the generic assignation [1].
I think there should be no constraint on those fields except for filling it on the transition if not yet filled.
[1] https://discuss.tryton.org/t/generic-assignation-of-document/280/3