It is more explicit and elegant but more of a pain to manage especially
with the new function. It was structured that way for other hosts'
secrets but it isn't really used in practice. We could just enforce a
convention such as a `hosts` prefix to contain those secrets.
I also added a conditional configuration for systemd-networkd and a
condition for the default which should be enabled when NetworkManager is
enabled. Ideally this should be the default when systemd-networkd is not
enabled but since they are the only network manager, we'll let it slide.
Re-added the setup with the traditional networking configuration since
I'm currently using GNOME which only integrates with NetworkManager
which is working alongside it.
systemd-networkd not being used at this point but I'm keeping it.
