Improve stopping and wiping behavior

* Progress indicator for stopping
* Progress indicator for wiping
* More logging during startup and stopping for debugging
* Put post wiping fragment into separate process
* Improve exiting behavior on stop/wipe
* Make wiping fragment display transition to stopping once wiping is
  done (by changing the status text view)
* Make stopping and wiping take at least 1 second so that the user can
  perceive what's going on if these finish very quickly on fast devices
* When detecting on startup, that the app is already stopping or wiping,
  display the stoppin/wiping fragment instead of failing silently
* Exit application when reaching STOPPED state, independent of lifecycle
1 job for !89 with 60-wiping-ui in 5 minutes and 58 seconds (queued for 1 minute and 41 seconds)
merge request