A20_minimum_buildroot

This is my playground with the different steps from a standard A20 buildroot image to a minimum and more or less GPL/LGPL or similar license free image.

This is only a TEST if this is possible and what are the problems. Find the corresponding docs/description here: https://github.com/tjohann/a20_minimum_buildroot_dev.git

Steps:
- i want to use MUSL, runit, socklog and toybox for the basic system.
- then active SELinux (or appamor or SMACK), seccomp, namespaces and cgroups