[RSSLO] DB BR 612 (STEAM version) fixes

Some Quality of Life modding for the 612 here.

• fixed missing passenger "5" cam interior model. The model is there but there InteriorGeometry field was left empty in the 612 A blueprint
• adjusted CabCam and natural sway parameters
• the desklight is now a soft nondistracting neutral white light, intensity slightly reduced
• lens flare rings removed and headlight (marker lights) intensity and radius reduced
• cab audio occlusion fixed. The default was weird, track sounds too loud. Now the engine is a wee bit louder and the cab isolation better.
• the strong dark cab glass tint is also removed, just a tiny bit was left.

Tags: br-612 db-612 fix mod rsslo steam