Esteemed maintainers,

Attached is a patch that I think improves the guix user experience on a
foreign distro. It creates a guix.sh init profile at /etc/profile.d (in the
same vein as flatpak with it's /etc/profile.d/flatpak.sh). I have been
using the init file on few of my friends computers with no regressions.

I have tried my best to emulate the commit-logs as seen from `git log
etc/guix-install.sh`. Please do let me know if I am doing anything wrong.
This is my first real contribution to a GNU project, ever. I am still a
n00b, and only have had experiences with GitHub based PRs so far, and still
have a lot to learn. Please forgive my klutzes.