Add a pastebin client to the next guixsd image release

[ng0 <ng0@libertad.pw>]

I think the next release image for GuixSD should include
wgetpaste as a tool. This would make it possible for people who
are stuck in the image and who are doing the installation, to
paste the config.scm or any other command output.

Are there any security concerns, or is this something we can do?
If the majority should be against it, another option I can think
of is that we add it to the documentation as a general suggestion
to search for "pastebin" with "guix package -s pastebin" and
install one of the available pastebin clients (there'll be more
than one at some point).
-- 
♥Ⓐ  ng0  | ng0.chaosnet.org