new PostGIS mirror on the italian National Institute for Astrophysics (inaf.it)

[Sandro Santilli]

The italian National Institute for Astrophysics (inaf.it) allowed us
to use their instance of GitLab to host a mirror of the codebase and
run CI pipelines, thanks to the facilitation of Alessandro Frigeri.

The mirror is automatically updated whenever the official code
repository receives new commits, with a direct push from Gitea.

You can see pipelines running here (showing 32bit troubles):
https://www.ict.inaf.it/gitlab/postgis/postgis/-/jobs

Since the same pipeline configuration could not be used for BOTH
the gitlab.com mirror and the inaf.it mirror (due to the need to
specify different runner tags) I've taken the chance to test
a different environment so at the moment inaf.it is testing
Debian 13 (Trixie).

Pipeline configurations have been moved under .gitlab/gitlab.com
and .gitlab/inaf.it to reduce top-level directories.

As the number of CI bots keeps growing I've moved the build status
table to a dedicated wiki page and updated the README.md file to be
more human/pager friendly. Please just add a link to the wiki page to
give an overview of which tests are failing and which are succeeding:

  https://trac.osgeo.org/postgis/wiki/ContinuousIntegration

Alessandro: thanks a lot for your help, and let us know how you'd like
the institute to be credited - I'm thinking a mention in the credits
page would be a good place ?

  https://postgis.net/docs/manual-3.5/postgis_introduction.html#credits_other_contributors

--strk;