Add the functionality to allow the user to update their Umbrel installation on the go, without having to manually install new releases or re-flash Umbrel OS image.
* Related: https://github.com/getumbrel/umbrel-manager/pull/21
* Related: https://github.com/getumbrel/umbrel-dashboard/pull/130
* Add signal watcher system with power cycle triggers
* Stop docker containers before system shutdown
* karen
* Run karen triggers async
* Allow specifying an event dir
* Check root_der exists
* Add space
* Check dependencies
* Make sure karen is run as root
* Make karen more kareny
* Mount signals dir from umbrel-manager on host