Reference OpenRC init script

Based on work by Pandu Poluan
Source: https://bitbucket.org/pepoluan/install-xe-guest-utilities-for-gentoo/
Update texts based on original init script
checkdom0 can't work without /proc/xenfs
Staying true to the original
Cleanup whitespaces
Moving some stuff...
Fixed inconsistent start-stop-daemon usage
Added note on CPU architectures