ci: enable serial console logging for CHV

[anokfireball]

also store additional host information for identifying CHV problems

requires the serial logging support from gardenlinux/package-libvirt#22

[anokfireball]

We do now have serial output from CHV! 🎉

> cat serial-VM-CHV-HV1.log | tail -n 40
[  OK  ] Finished systemd-udev-trigger.service - Coldplug All udev Devices.
[  OK  ] Finished systemd-tmpfiles-setup-de…Create Static Device Nodes in /dev.
[  OK  ] Reached target local-fs-pre.target…Preparation for Local File Systems.
         Starting systemd-udevd.service - R…ager for Device Events and Files...
[  OK  ] Started systemd-udevd.service - Ru…anager for Device Events and Files.
[  112.358837] cloud-init[202]: Cloud-init v. 25.1.2-0ubuntu0~24.04.1 running 'init-local' at Tue, 26 Aug 2025 10:08:57 +0000. Up 111.33 seconds.
[  OK  ] Found device dev-hvc0.device - /dev/hvc0.
[ TIME ] Timed out waiting for device dev-d…T.device - /dev/disk/by-label/BOOT.
[DEPEND] Dependency failed for systemd-fsck…m Check on /dev/disk/by-label/BOOT.
[DEPEND] Dependency failed for boot.mount - /boot.
[DEPEND] Dependency failed for unattended-u…ice - Unattended Upgrades Shutdown.
[DEPEND] Dependency failed for boot-efi.mount - /boot/efi.
[DEPEND] Dependency failed for local-fs.target - Local File Systems.
[  OK  ] Stopped systemd-ask-password-conso…equests to Console Directory Watch.
[  OK  ] Stopped systemd-ask-password-wall.…d Requests to Wall Directory Watch.
[  OK  ] Reached target timers.target - Timer Units.
[  OK  ] Listening on systemd-sysext.socket…tension Image Management (Varlink).
[  OK  ] Reached target cloud-init.target - Cloud-init target.
         Starting console-setup.service - Set console font and keymap...
[  OK  ] Reached target getty.target - Login Prompts.
[  OK  ] Reached target getty-pre.target - Preparation for Logins.
         Starting setvtrgb.service - Set console scheme...
[  OK  ] Reached target paths.target - Path Units.
[  OK  ] Reached target sockets.target - Socket Units.
[  OK  ] Listening on dbus.socket - D-Bus System Message Bus Socket.
         Starting apparmor.service - Load AppArmor profiles...
         Starting dbus.service - D-Bus System Message Bus...
[  OK  ] Started emergency.service - Emergency Shell.
[  OK  ] Reached target emergency.target - Emergency Mode.
         Starting ldconfig.service - Rebuild Dynamic Linker Cache...
         Starting systemd-binfmt.service - Set Up Additional Binary Formats...
         Starting systemd-tmpfiles-setup.se…e Volatile Files and Directories...
[  OK  ] Started dbus.service - D-Bus System Message Bus.
[  OK  ] Finished console-setup.service - Set console font and keymap.
[  OK  ] Finished setvtrgb.service - Set console scheme.
You are in emergency mode. After logging in, type "journalctl -xb" to view
system logs, "systemctl reboot" to reboot, or "exit"
to continue bootup.
Press Enter for maintenance
(or press Control-D to continue): %