Add extension https://github.com/bladebaillio/soft-body-extension.git

[bladebaillio]

GitHub repo: https://github.com/bladebaillio/soft-body-extension.git
Forum post: https://forum.makecode.com/t/soft-body-rope-etension/33805
Demo: [INSERT DEMO LINK - NOT REQUIRED]
Description: An extension for Softbody physics on Makecode Arcade. This extension can be used to make a variety of games that need rope physics, it's also great for making procedurally animated creatures!

[bladebaillio]

I was thinking about adding a demo latter if that is a possibility. Thank you, UnsignedArduino!