ensure power-down

[tehn]

randomly there can be a stop-job that makes power-off take a long time (a full 1:30)

it's sometimes more frequent when battery powered, but not always.

to replicate:

• when battery powered, sudo shutdown now (via wifi or norns menu)
• then connect usb-serial to laptop
• you'll see the count down

we need to identify why and which job takes so long at shutdown and make sure we have a quick shutdown. it's very confusing to have the device not shut down when you don't have a terminal hooked up.