Remove cold slowdown entirely

[UrsulaMejor]

1) replace it with a "shivering" status effect

2) you have a chance to roll "shivering" when you are below a certain temperature, and the chance + duration scales with how far below that you are

3) much like clicking on the "burning" status effect causes you to attempt to roll it out, clicking on the "shivering" status effect causes you to shake and rub yourself warmer, reducing the duration