doc: Removing much of Binary Installation (was: Feedback of the GNU Guix manual)

["pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de>]

Thank you Matt for the suggested diff.

Yes, I agree some simplification as you suggested would be beneficial,
so that the description of Binary Installation looks as simple as it
really is.  (In particular, I have witnessed people, to whom I had
suggested Guix, fail at trying Guix because they tried Guix System on a
not libre-friendly laptop, when they could/should have tried Binary
Installation.)

> - Places
> directions for 'guix-install.sh' after directions to use
> distribution-specific package managers, giving preference to those
> simpler install processes over the more manual 'guix-install.sh'
> process

I don’t feel qualified to judge, but is this the preference?  Arch wiki
advises against the Arch AUR package: “Therefore, after updating Guix
once, the AUR advantage really turns into a disadvantage, as there will
be many unnecessary files in the /usr file tree that are part of the
Guix AUR package but that are never used by Guix anymore.  Therefore,
consider using the manual installation.” [0]

The reason of existence for these distribution packages is probably
similar to the reason why the Binary Installation section exists.

As for the suggested diff where much of Binary Installation gets
removed,

> -@item
> -@cindex substitutes, authorization thereof
> -To use substitutes from @code{@value{SUBSTITUTE-SERVER-1}},
> -@code{@value{SUBSTITUTE-SERVER-2}} or a mirror (@pxref{Substitutes}),
> -authorize them:
> -
> -@example
> -# guix archive --authorize < \
> -     ~root/.config/guix/current/share/guix/@value{SUBSTITUTE-SERVER-1}.pub
> -# guix archive --authorize < \
> -     ~root/.config/guix/current/share/guix/@value{SUBSTITUTE-SERVER-2}.pub
> -@end example
> -
> -@quotation Note
> -If you do not enable substitutes, Guix will end up building
> -@emph{everything} from source on your machine, making each installation
> -and upgrade very expensive.  @xref{On Trusting Binaries}, for a
> -discussion of reasons why one might want do disable substitutes.
> -@end quotation

I disagree with this chunk.  This must stay.  Not enabling substitutes
is an option in guix-install.sh and the Guix System installer.  Users
might want to enable substitutes later on.

Regards,
Florian

[0] https://wiki.archlinux.org/title/Guix