Systemd Upgrade Patches

So far version 211 seems to be working in a basic capacity and passes the simple and login tests. At this point I'd like more people to test out the patch set for more complicated sets of services.

TODO:
Rebase the changes from edolstra/systemd. I would prefer that this be done by creating a NixOS/systemd repository to keep track of the changeset.

Integrate our networking modules with systemd-networkd

Fix visible errors generated from some of the services (The rebase will cover some of these).

Perform more testing of unintended side effects.

Test the arm patch which I'm sure doesn't even apply correctly anymore.