accesspoints: add wifi clients metrics into prometheus

`wifi_network_clients` exposes the amount of connected wifi clients

playbook_provision_accesspoints.yml

@@ -32,10 +32,20 @@
       notify:
         - restart prometheus-node-exporter-lua
 
-    - name: install prometheus-node-exporter-lua-wifi
+    - name: uninstall vanilla prometheus-node-exporter-lua-wifi
       opkg:
         name: prometheus-node-exporter-lua-wifi
-        update_cache: yes
+        state: absent
+      notify:
+        - restart prometheus-node-exporter-lua
+
+    - name: install custom prometheus-node-exporter-lua-wifi
+      copy:
+        src: files/wifi.lua
+        dest: /usr/lib/lua/prometheus-collectors/wifi.lua
+        owner: root
+        group: root
+        mode: 0755
       notify:
         - restart prometheus-node-exporter-lua