* nixos/earlyoom: bring the module up to date
Removes deprecated option `ignoreOOMScoreAdjust`, introduces `killHook`
as a replacement for `notificationsCommand`, and adds an `extraArgs`
option for things not covered by the module.
* nixos/earlyoom: add nixos test
* nixos/earlyoom: add reportInterval
Allows setting the interval for logging a memory report. Defaults to
3600 following upstream
(https://github.com/rfjakob/earlyoom/blob/master/earlyoom.default#L5)
to avoid flooding logs.
* nixos/earlyoom: add free{Mem,Swap}KillThreshold
Fixes https://github.com/NixOS/nixpkgs/issues/83504
