feat: add timer for secret thing

hosts/ami/default.nix

@@ -38,4 +38,23 @@
   ];
 
   services.syncthing.enable = true;
+
+  systemd = {
+    services.register-thing = {
+      serviceConfig = {
+        Type = "oneshot";
+        User = "maintainer";
+        ExecStart = "/home/maintainer/register-thing/thing";
+      };
+    };
+
+    timers.register-thing = {
+      wantedBy = ["timers.target"];
+      timerConfig = {
+        OnUnitActiveSec = "1m";
+        RandomizedDelaySec = "1m";
+        Unit = "register-thing";
+      };
+    };
+  };
 }