xhci refactoring: sperate out all xhci-related code to its own directory

xhci: refactoring: move out xhci controller code

make printf function available for not-main userland files

xhci: refactoring: use SlotXHCI instead of long parameter list

xhci: refactor and seperate out commands

xhci: refactor trbRing functions to seperate file

vga: add scrolling when exceeding maximum default line count

shell / ioManager: don't allow backspace when input buffer is empty

fix issue #3: crash when running an unknown program

xhci: show device information using usb strings

xhci: print basic usb device information

xhci: clean up slot initialization

xhci: send get device information command to attached usb devices

xhci: configure endpoint

xhci: send address device command

fix weird problems with getPhysicalAddress system call

xhci: request a slot for each activated port

enable xhci ports with a connection

fix issue with printing where the first message would not get printed

create async xhci command function using events

trigger interrupts from xhci controller

fix problem where page fault happens because not the whole string is mapped in a insertString system call

refactor syscall.c

fix issue vga driver: newline doesn't move cursor #2

use sleep function for xhci driver waiting for the controller to start

add sleep function to PIT driver

add system time readout

add basic PIT timer outline

receive xhci events

try initializing xhci hub