xinit: Trigger hudctrl at boot

The *hudctrl* service remotely controls Firefox on the Basement HUD
machine.  It uses Firefox Marionette over TCP, and is itself controlled
by an HTTP API.

When the HUD machine starts up, it sends its monitor configuration to
*hudctrl* and tells it the display is ready to be controlled remotely.

For now, *hudctrl* is hosed on Rosalina.  I will eventually move it to
the new metrics server, once it's built.

overlay/home/user/.xinitrc

@@ -8,4 +8,13 @@ export TZ
 
 systemctl --user import-environment DISPLAY TZ
 systemctl --user start firefox-marionette.socket firefox
+
+BASE_URL=http://rosalina.pyrocufflink.blue:8000
+xrandr --listactivemonitors \
+    | curl "${BASE_URL}"/display/monitors \
+        -H 'Content-Type: text/plain' \
+        --upload-file -
+curl "${BASE_URL}"/display/up \
+    -d port=2829
+
 exec openbox