Reorganization of some Shape .ts files

[Connierollstheball]

While messing around in the files, I noticed that there were some small .ts files that didn't really make sense (at least to me) to exist on their own. I think it would be just a bit better if stuff like Small Duct Fans or Round Bumpers were initiated/defined/whatever-the-right-keyword-is in duct_fan.ts and abstract_bumper.ts instead of them having their own standalone .ts files.

I've done this for Bumpers, Signs, and Duct Fans. I've also tested this and noticed no performance drops.