Refactor reboot guard services #11
Description
Reference: https://gerrit.openbmc.org/c/openbmc/phosphor-bmc-code-mgmt/+/56998
Can the reboot guard services be refactored into one?
Also need to address the scenario where the updater app crashes and the reboot guard is left enabled. Could the reboot guard be disabled automatically if the updater service restarts via systemd dependencies?