Allowing administators to change status of parcel back to SCHEDULED

Hello

We start to receive requests from several users ( 3 in a week) who put their parcel in READY FOR SAFETY VALIDATION but with errors (either forgetting to add a sample, having put it with dangerous good flag when this was not necessary..) and would like to edit them again. I wonder if, as manager, we couldn't have the possibility to put such parcels back to SCHEDULED state after checking that they were not physically sent to ESRF, basically allowing us to change the status to "SCHEDULED" for any parcel for which the status is READY, APPROVED,INPUT, REFUSED, SENT. That way we could help the users.. What do you think?

By the way: I see great changes since the last version I saw in July ! @bocciare @loic.huder @demariaa : very well done!