autoprovision: split script+unit into separate files

Now that we're using Jinja to render the kickstart scripts, we can
separate out scripts, systemd unit files, etc. into their own files and
`include` them.  This makes editing them much easier, especially since
syntax highlighting will work correctly.

autoprovision.ks.j2

@@ -0,0 +1,16 @@
+%post
+cat > /root/.ssh/authorized_keys <<EOF
+expiry-time="$(date -d +1hour +%Y%m%d%H%M)",restrict,pty ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICoOO/ZYMxRgmyvqZwGN3NM5pHyh3NBdC7iZrXIopt93 Host Provisioner
+EOF
+
+cat > /usr/local/libexec/notify-online.sh <<'EOF'
+{% include "notify-online.sh" %}
+EOF
+chmod +x /usr/local/libexec/notify-online.sh
+
+cat > /etc/systemd/system/notify-online.service <<'EOF'
+{% include "notify-online.service" %}
+EOF
+
+systemctl enable --no-reload notify-online.service
+%end