Hello Guix!

Please find the attached patch-set.

NOTES:
[1] New module gajim.scm was created, as Gajim project has quite a 
packages of it's own. The idea is similar to linphone.scm.
[2] Once users get used to gajim-next and gajim-omemo-next, we can 
deprecate older package definitions gajim and gajim-omemo.

Regards,
RG.