Map sdl keycodes.

I will update this PR as I map more keys later tonight (and in the future).

My [Hello World](https://github.com/Phrohdoh/knightos-helloworld) project is where this will be applied for testing.
There is a different key that should be mapped to Y (on the keyboard), and that's 1 (on the calc). The calculator keymap has an alpha mode where letters are written next to keys and you can use them with a modifier key. Look up a pic of a calc and look for the purple letters next to each key. This is the keys that KnightOS maps to each of those letters.