RISC-V support in slapos

This is the first part to support Risc-V architecture. The goal is first to have a slapos-sr-testing running with at least 1 SR PASSED.

Note that the Risc-V machine is running Fedora 40 (very recent with gcc14) so some of the work is to support Fedora (vs Debian) and some of the work is to support gcc14.