housekeeping: Add systemd OOM notification module
Note that we only notify if a unit (scope/service) is actually stopped due to OOM. This will not catch certain other cases where e.g. a delegated cgroup receives an OOM event.
Note that we only notify if a unit (scope/service) is actually stopped due to OOM. This will not catch certain other cases where e.g. a delegated cgroup receives an OOM event.