ETS2 - Iveco Turbostar Update V1.1 (1.37.x)

Changelog:
- Added air horn accessory slots
- Added beacon accessory slots
- Added compatibility for Accessory Pack

TO BE FIXED:
– Retarder sound (waiting for SCS Modding Wiki guides)
– Air Horn sound (waiting for SCS Modding Wiki guides)

Authors: Author: Ralf84 | Credits: Scaniaman1989, Fabian Modding, Ventyres, Dani Lee, Ekualizer, Peerke145, Kriechbaum, Mixer66, Baltazar