Update to 1.10

This updates the debian-experimental branch to 1.10. I've also added salsa-ci (which will fail when enabled in this repo until we update the upstream-experimental branch here as well). I can open MRs for upstream and pristine-tar branches as well (or get added to the xorg-team) if that makes sense.

The diff is hard to review as I needed to update debian-experimental with debian-unstable first so looking at the recent commits is likely simpler.

Also happy to upload to experimental, just let me know how to best handle it. Would be awesome to get that updated as it's needed for newer wlroots and running with locally built packages is cumbersome on multiarch development systems.

Closes: #1106487