Accessibility in Guix

[Julien Lepiller]

Hi Guix!

I think in order to reach out to more people, accessiblity is an
important topic. I've talked with Irina during the Perl and Guile days,
and fixed orca (it didn't work because of failures when loading
pyatspi).

In order to make our system accessible from the start, we obviously
need an accessible installer. With Irina and later with Jean-Phillipe
from Hypra, I collected a list of items we should have in the installer
for blind and visually impaired people:

- A way to activate accessibility options from the start of the system
  (it doesn't need to be on by default if we make sure to document it
  in the manual). For instance, it could be the first item in the first
  menu, or a keyboard shortcut.
- Screen reader technologies: there are a few accessibility
  technologies for that. Since the installer is on a tty, we could use
  brltty that is able to talk to braille output, and we could use
  speakup, a kernel module that is able to read a tty and use voice
  synthesis hardware and software.
- We should have an option to build a system with accessibility
  features, probably via a menu to select the kind of accessibility
  feature one needs (it should be a gnome system, with orca running).

We should probably talk to youpi from Debian, since he worked on the
accessibility features of the Debian installer.