[ADD] barcode nomenclature for tare
[ADD] tare field on pos.order.line model
[ADD] Tare button in PoS numpad
[IMP] handle correctly different UoM
[IMP] add warning at checkout if qty <=0
[IMP] display gross and tare weight for each line
Co-authored-by: François Kawala <francois.kawala@gmail.com>
Co-authored-by: Sylvain LE GAL <sylvain.legal@grap.coop>