Core of the Kernel

[pahmann]

Fill the core of the kernel document.
Come to a base configuration.
Setup a CI with Systems WG building and booting the core Kernel.
Base will be on tiny config to be extended and run on most likely qemu hardware.

Cross WG activity between Systems, LFSCS and Arch WG

This is a follow up action item from the Lund workshop:
https://drive.google.com/drive/folders/147nRSiEjs8USRetnSy0lyDPbtqAc9O63