GNOME Gitlab migration

Hi,


As mentioned in the other thread, there is now a git repository for 
AbiWord hosted on GNOME gitlab infrastructure.

See https://gitlab.gnome.org/World/AbiWord for the details.

The SVN repository has been turned to read-only. I will update the 
documentation and everything.

Currently, only Jean and I have Maintainer rights, as I couldn't find 
other contributors. But if you had commit access, let me know your 
account name on https://gitlab.gnome.org/ and I'll add you.

I would like to thank Carlos Soriano and the GNOME infrastructure team 
for hosting the source code.

If you have questions, don't hesitate.

Cheers,

Hub