Now with host-specific and user-specific modules, we can now start
remove parts of the modules with my configurations on them that are
otherwise intended for the entire cluster.
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.
