Make systemd send errors to be shown as notifications in gnome

Submitted by Pacho Ramos @pachoramos1

Link to original bug (#707138)

Description

Not sure if g-s-d is the right component as I don't know what would be responsive of communicating with systemd :/

Sometimes it's a bit easy to start to see some service failed to start at some point but, if I don't see journalctl often, I can easily miss this problem or any other.

Then, I think would be really interesting to let systemd send errors to be shown as notifications from gnome desktop

Thanks a lot!

Version: 3.8.x