Bare-metal OS stuff

This is a in-progress bare-metal os for the Raspberry PI 4. Long-term goal is to implement enough syscalls that a "Hello World" in C is runnable.

Resources

https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials

https://github.com/rlepigre/bare-metal-aarch64

https://github.com/isometimes/rpi4-osdev/

https://github.com/bztsrc/raspi3-tutorial

https://jsandler18.github.io/

https://github.com/google/aarch64-paging