Ignore 1-Wire sensor departure, just react to timeout

[climategadgets]

Existing Behavior

1-Wire sensor departure immediately propagates to the control system and makes it act prematurely, as jitter and short blackouts are possible.

Desired Behavior

If/when a 1-Wire sensor departs, the departure is not propagated down the control flow immediately, but only after a given timeout when the sensor is considered stale.

Corollary

Hardware failure notifications must be handled outside of control flow.