Outdated Crash Junctions 0.54

I've updated the format for the level to the new post-0.9 standards, so the scenarios and campaign should again work properly. The old format is being retained, though, so it will still remain compatible with older versions of BeamNG for the time being. I've also adjusted several timers, and added rain particles back into the level.

I've also added the new "Streetcar Test" scenario, an objectiveless sandbox 'scenario' built to let you play around with the streetcar on the limited stretch of track in the map. Currently, it features the same preview image as Evening Post, but it'll do for now.