Offroad chassis for standard trailers v2.1

Offroad chassis for standard trailers - Changelog v1.3 Added a 3-axle off-road chassis for the SCS container ship-for one body!!!Opens from level 15!!! Added off-road 3-axle chassis for these types of single trailers - # 1 is-scs.box-(All types of bodies from SCS,awning,refrigerators,isometric, etc...