Create a replacement for upstart-watchdog

upstart-watchdog is a set of Upstart jobs which monitor job failures in system and session Upstart and reboot the machine if respawn limits have been reached.

My understand is that Systemd has a kind of built-in functionalities similar to this one. However upstart-watchdog also prevents reboot if it just happens recently (and also in .writable_image mode). It would be nice to have because we don't want to have a reboot loop (a partially working phone is better than a phone which reboot constantly). I'm not sure if we can do something like that in Systemd.