Allow unprivileged dbus method calls

[jfhbrook]

In #30 , I was able to get the systemd service running, and was able to run plusdeckctl commands with sudo.

However, unprivileged access is eluding me. The intent is that unprivileged users in the plusdeck group may have full access to the service. Currently what works is listening to signals (plusdeckctl subscribe), as well as property access (plusdeckctl config show). Unfortunately, method calling (plusdeckctl eject) is not working.

I believe the issue lies with systemd, either with some capacities I have to manually set, or with some settings I need in polkit. For more information, see these discussion threads:

https://unix.stackexchange.com/questions/790750/dbus-policy-that-allows-group-to-access-system-service
https://discussion.fedoraproject.org/t/dbus-policy-that-allows-group-to-access-system-service/144265

[jfhbrook]

Potentially useful links:

• https://www.freedesktop.org/software/polkit/docs/latest/polkit.8.html
• https://askubuntu.com/questions/1387029/debug-policykit-rules

[jfhbrook]

Probably fixed in #35, but going to leave this open until I can resolve #34 and test.

[jfhbrook]

This seems to be working!