Start as non-root using capabilities

[eyedeekay]

Is your feature request related to a problem? Please describe.
This application can be run without root and without docker using capabilities. This should be facilitated when the user installs the application.

Describe the solution you'd like
Capabilities required for creating TUN devices on linux should be made available to this application when installed on Linux.

Describe alternatives you've considered
Dropping privileges is unsupported in Go. Go uses capabilities.