Basic round robin scheduling is used

Now the root module is the common bits and not the arch bits. This
should be more friendly to eventually getting the aarch64 port working
again.

There were some insanely cursed and hard to debug issues on a ThinkPad I
had with a small cropped framebuffer on Libreboot + SeaBIOS.

I noticed the existing implementation had issues scrolling in some cases

Like the PIT demo, this gives a periodic message much more efficiently.
Scheduling is very close!

Successfully set up the 8254 and 8259 for the sole purpose of
calibrating the TSC on AMD.

While getting the TSC rate is easy on Intel, I need to set up a delay
loop for AMD to compare to the PIT frequency. All of this logic will
be in a future commit.

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