Experimental Gavril MD-Series Mega Hauler 1.2

Removed the school buses exhaust from the configs to stop the duplicated exhaust bug,
Renamed the school buses exhaust slot,
Hopefully fixed a bug where the cargo box loads were spawning at max weight by default,
Added what I believe is the correct UV map from the T-Series cargo box to skin this mods cargo box (this mod uses the T-Series cargo box). The UV is located in the file path "vehicles\md_series\busexperiment\cargobox_md".

Small update that changes the skin slot name on the dryvan so it supports the MD-Series dryvan skins, its a bit buggy as modded skins seem to be off centre on the side but unfortunately I don't think I can do anything about it due to the dryvan model being from the T-Series.
Also deprecated the Main Fuel Tank due to some instability issues, it is still selectable though if you want to use it.