[Feature] Alarm for Inactivity

[jurassicplayer]

Is your feature request related to a problem? Please describe.
There is currently no good way to automatically suspend/shutdown the device if there is no general input activity.

Describe the solution you'd like
Implement an alarm that can be triggered if there has been no general input activity for a customizable length of time during which input is monitored to reset the alarm timer.

Describe alternatives you've considered
The day that Valve implements using the same power settings as desktop mode.

[yrto]

This would be a killer feature for us running SteamOS (eg: ChimeraOS) on desktop + TV. There is no reliable way to dim the screen or suspend the system after a set amount of time idling.