Module for reading service credentials

[cedws]

I would like a module that can read credentials when the current program is running as a systemd service.

This should be fairly simple and a small amount of code. I'm willing to send a PR at some point.

[lucab]

Thanks, that would be much appreciated! If you want a comparison with native bindings for another language (Rust), there is this one still in fly: https://github.com/lucab/libsystemd-rs/pull/98