Cummins 903 VTA 660 v1.1

The mod adds a new engine Cummins 903 VTA 660 with its sounds.
The mod is based on sounds from Kriechbaum.

- New engine start sound;
- New engine sounds with no load;
- New sounds without fuel;
- Aligned engine sounds under load;
- Volume balancing.

Supported trucks:
- Kenworth K100-E by Overfloater;
- Freightliner FLB by Harven;
- Freightliner Argosy by Harven.