Is your feature request related to a problem? Please describe.

Currently, subspace creates wg0 device and configuration files for clients always wg0.conf.
I would like to change.

Describe the solution you'd like

add --device-name=<string> flag to subspace command and change config filename to (device name).conf.
I believe device name and config file name should be the same to avoid confusion.

Describe alternatives you've considered

I don't have any plan B.