[Announcement]: Guile repositories' new home

Hi all,

As many of you know, the official GNU Guile repository is now hosted in 
Codeberg, under the `guile` organization:

https://codeberg.org/guile

During these days, thanks to Ludovic's help, we managed to move also 
some adjacent projects to the same organization: Guile's JIT compilation 
library, Lightening, and the Fibers library.

Both projects were scattered around the universe (lightening was in 
Andy's personal gitlab account and fibers in his github, until its 
recent move to a separate organization in Codeberg), so we consider this 
an improvement.

Both projects have CI enabled for testing, thanks to Codeberg.

We still need to fix a couple of links here and there, specially in 
fibers, and import the issues and PRs that Lightening had, and proceed 
to archive their original locations.

I'd like to take advantage of the new location to encourage you to take 
a look into them and understand how they work (both are very interesting 
and their bus factor is pretty high) and contribute. Now more people 
should have access and the maintenance should be a little bit better.

All the best,
Ekaitz