Update Camera Shake 2D with feature requested in #2429

[DragonMoffon]

Thank you, @bunny-therapist, for the feature request!

Also adds the context manager interface, allowing for the following neat code:

with self.shake, self.camera.activate():
  # draw commands that want to be drawn with screen shake,
# outside of the with block the shake has been removed, and the camera has been deactivated.

closes #2429 and #2446 (Thank you for the PR, but due to the extra feature I've made my own PR)