Convert to meson build system

• Add meson support to libvirt-glib !9 (merged)
• Convert libvirt-ci to use meson for libvirt-glib project libvirt-ci!69 (merged)
• Convert GNOME build deps to use meson for libvirt-glib project https://gitlab.gnome.org/GNOME/gnome-build-meta/-/merge_requests/971
• Convert GNOME boxes flatpak to use meson for libvirt-glib https://gitlab.gnome.org/GNOME/gnome-boxes/-/merge_requests/397
• Convert virt-viewer to use meson for libvirt-glib project virt-viewer/virt-viewer!52 (merged)
• Remove autotools support from libvirt-glib !10 (merged)