FR: support an "only when idle" mode

[boredsquirrel]

Describe the bug

Not sure if FRs go here.

I would like to discuss this feature. Check the system power consumption over the last x minutes, if it didnt exceed x % CPU usage for over x seconds (random spikes may happen) then it is "idling"

Only in this state initiate the update, configured as automatic.

Reproduction steps

None

Expected behavior

Above

Actual behavior

No option like that

System details

Fedora Kinoite (OCI image version from ublue)

Additional information

No response

[jlebon]

Related: #4676, #1730