Corrected Max Masses

Some basegame auger wagons cannot be filled to their capacity, since maximum allowed mass for road use was configured and not the one for field work.
This mod adds an additional shop object with corrected max mass for each affected auger wagon. Following vehicles are corrected/improved:
Bergmann RRW 500: 52 tons
Demco 2200 Dual Auger Grain Cart: 72 tons
Elmers HaulMaster: 65 tons
HAWE KUW 2000: 28 tons
HAWE ULW 4000: 48 tons