Show progress while the smoketest waits on a VM

The waits for SSH, GNOME and a reboot say what they're waiting for and
repeat it once a minute, and the base build says when it's waiting for
cloud-init, installing GNOME and shutting down.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/smoketest.sh

@@ -261,7 +261,9 @@ build_base_image() {
     vm_start "$build" "$build/disk.qcow2" -cdrom "$build/seed.iso"
     trap vm_kill EXIT
     wait_for_ssh
+    echo "Waiting for cloud-init to set up the VM's user..."
     vm_ssh 'cloud-init status --wait' < /dev/null > /dev/null || true
+    echo "Installing GNOME (vm/provision.sh)..."
     vm_put "$(sibling_dir)/vm/provision.sh" /tmp/provision.sh || die "Couldn't copy provision.sh to the VM."
     vm_exec 'sudo bash /tmp/provision.sh' || die "Provisioning failed; see $build/build.log"
     vm_stop