upgrader: add extra_playbook when running upgrader playbook
https://lab.nexedi.com/nexedi/slapos.package/-/merge_requests/213 was supposed to remove SSH password authentication for all vifib machines except ORS, however it did not (and I somehow didn't see it when testing before it was merged).
This happenned because extra_playbook variable is added as an extra var when running upgrader-run.yml, but then upgrader-run.yml runs vifib-upgrade.yml without adding the extra_playbook variable, so vifib-server roles is ran without extra_playbook defined.
The fix is to add extra_playbook as an extra var when running the upgrader playbook. For ORS this will add back root password authentication, and for non-ORS the only difference is extra_playbook will be defined and equal to '' instead of undefined, but this should not cause any issues since there are no checks which rely on whether extra_playbook is defined or not.