nix: Make nix the root

Which means now I'll have to think about real prefixes in commit names.

unprocessed/config/automatrop/roles/system/handlers/main.yaml

@@ -0,0 +1,10 @@
+- name: Reload systemd daemon
+  ansible.builtin.systemd:
+    daemon_reload: true
+  listen: systemd changed
+  become: true
+
+- name: Warn about changed Panfrost config
+  ansible.builtin.debug:
+    msg: The Panfrost display driver configuration was changed, but needs a reboot to be applied.
+  listen: panfrost config changed