Ability to signal host shutdown

[jasonyates-thg]

It would be useful to be able to signal the host system to shutdown in the same fashion we are able to signal the system to reboot via writing /worker/reboot

My use case is a deprovisioning workflow that erases disks, profiles the hardware and then ideally shuts the system down

[jacobweinstock]

This is being tracked with tinkerbell/roadmap#29. This will most likely be added as a built-in to tink worker in the future. For the moment, an Action like https://github.com/jacobweinstock/waitdaemon can shutdown a host.