Add bolt task to return unit state in a more parsable way

[rwaffen]

bolt task run systemd::systemctl_show unit_name=puppet.service -t controller-0

Started on controller-0...
Finished on controller-0:
  {
    "MainPID": "686",
    "LoadState": "loaded",
    "ActiveState": "active",
    "SubState": "running",
    "UnitFileState": "enabled"
  }