Remove extending the Javascript builtin objects

- Remove extending the Math & CanvasRenderingContext2D classes.
  - It was messing up the typescript 4.9+
  - Using the built-in roundRect function
  - Adding global clamp function
- Add some type corrections in litegraph.d.ts
- Fix a couple of build issues

Co-authored-by: Ranuka Perera <premium@sawrc.com>
Co-authored-by: Moritz Ulmer <moritz.ulmer@posteo.de>