ETL Frostbite (v9) addon

Visual overhaul of the original Frostbite which was created by Moonkey. All credit for the map resides with Moonkey. As part of ET: Legacy development effort proven community maps are selected due to polished gameplay and receive a visual overhaul. For Frostbite that included a more nighttime setting related lighting, cleaner collision for railings and a colour coded facility structure to simplify call-outs to teammates.