Remove requirement to run as root

[TinyTheBrontosaurus]

I assume this is possible, but it will be difficult when it comes to mounting. But I get nervous when directories are being mkdir'd and rm'd as root.

[ahnooie]

Agreed, definitely want to get it working as non-root soon. The ARM could either su to an underprivileged user for most tasks, or sudo to root only when it needs it.

[2long1]

Adding User=foo to the arm@.service file would cause the identify script to be be run as the user foo. With a judicious use of sudo, you could probably drastically reduce what runs as root.

[muckngrind4]

Added feature in commit d3b9c6d