Add Galacti Unicorn LED Matrix abstratction layer

[seletz]

I think i want to use the galactic unicorn as "display". To test this, I want a raylib emulation in the mac native build. Once we have this, we can quickly iterate on UI layout ideas.

We should use the existing c library from pimironi as a guide for the API -- we eventually need to add microzig code to support this and we likely will translate the c library to zig for that, so the api needs to be very close to what we will get then to ease integration.