Since GNOME 44, extension schemas are compiled at install time.
At the time GNOME 46 is released, this will be all supported versions,
so start relying on it and drop the old compatibility
code.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3042>
GSettings schemas are now compiled at install time, so it is no
longer necessary to include the compiled schema in the archive.
However the `gnome-extensions pack` command hasn't been adjusted,
so that it can still be used to produce valid archives for all
supported versions.
To not let that code linger forever, error out when building
a version where GNOME 44 is the oldest supported release.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2639>
Error reporting is useful when used interactively, but often undesirable
when used in scripts. Account for that with a common --quiet option,
which is more convenient than redirection stderr to /dev/null.
https://gitlab.gnome.org/GNOME/gnome-shell/issues/2391
The gnome-extensions tool code is really independent from the rest of the
code base, and could be used either as part of the gnome-shell build or as
stand-alone project (for example for the extension-ci docker image).
We can actually support both cases by moving the code to a subproject.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/877
