Driver Wage Tweaks - Lower Driver Costs V1.0

Lowers hire cost and salary pressure for AI drivers.

Changes:
driver cargo market revenue coef per km: 1.0
driver hire cost: 400
driver maintenance cost: (0.8, 1.2)
driver revenue coef per km: 0.95
minimal driver salary: 120

Compatible with:
ATS 1.60 and 1.61

Authors: modsclub