libvirt-executor improvements

A bunch of improvements to the libvirt-executor, with the major one being that the image is now built in the arch-boxes projects (arch-boxes!200 (merged)), instead of on each runner.

Please see the commit messages for more details.

---

Deployed on runner1.archlinux.org and secure-runner1.archlinux.org.

roles/gitlab_runner/files/libvirt-executor-update-base-image

@@ -30,9 +30,7 @@ qemu-img convert -f qcow2 -O raw Arch-Linux-x86_64-basic.qcow2 Arch-Linux-x86_64
 
 loopdev="$(losetup --find --partscan --show "${image}")"
 mount --mkdir "${loopdev}p3" mnt
-
-arch-chroot mnt pacman-key --init
-arch-chroot mnt pacman-key --populate
+mount --mkdir --bind -o ro /etc/pacman.d/gnupg mnt/etc/pacman.d/gnupg
 
 arch-chroot mnt systemctl disable systemd-time-wait-sync
 arch-chroot mnt pacman -Sy --noconfirm --needed archlinux-keyring
@@ -47,8 +45,8 @@ rm -f mnt/etc/machine-id mnt/etc/hostname
 
 cp -a mnt/boot/{initramfs-linux-fallback.img,initramfs-linux.img}
 
-rm -r mnt/etc/pacman.d/gnupg/{openpgp-revocs.d,private-keys-v1.d}/
-arch-chroot mnt pacman-key --delete pacman@localhost
+umount mnt/etc/pacman.d/gnupg
+rmdir mnt/etc/pacman.d/gnupg
 umount mnt
 losetup -d "${loopdev}"
 loopdev=""