more devices could have lifecycle::Indicator #988
Description
as of #754 we've got a struct Indicator that explicitly tracks the current state w.r.t. the device Lifecycle state machine, and comes with some logic to ensure that state transitions are valid.
I don't have a specific design in mind yet, but Indicator relies on Lifecycle implementers calling its functions at the right points in their implementations of the trait. it feels like Indicator is a good check that drivers of devices (propolis-server, propolis-standalone) are conforming to the state machine, and that really we could have an Indicator on every device. then it might be plausible to not require manually calling Indicator::start etc to keep its tracking of the lifecycle state in sync?