Device Owner Permission

The "Device Admin" permission is not enough (anymore) for all things we would like to do. These include:

• fmd delete (on Android >= 14, see #199 (comment 1975457249)).
• fmd reboot (#191)
• fmd bluetooth on/off (#201 (closed))

For these things, we need to be "Device Owner".

This ticket is to track the research into Device Owner (the documentation is spare/spread out...). It's a bit harder to become Device Owner, it is more privileged than Device Admin, and the implications of being one are not quite clear to me yet (e.g., how to I un-become Device Owner?).