[MTR3/4] Eurostar class 373

Added Buffet Carriage Updated the Following Liveries onto MTR4:

• SNCF TGV Livery
• GNER Livery
• EuroStar Old Livery (first ever logo)
• EuroStar New Livery

Added the following Liveries:

• SNCF TGV Livery
• GNER Livery
• EuroStar Old Livery (first ever logo)

Fixed the following reports:

• Interior being weird
• train doors not having sound
• weird carriage formation

Added new car to make the train an exact replica of the IRL train

Added new door sounds

Smoothed the Train

added class 373 with the latest Eurostar livery