[ticket/16944] Unify footer code and clean up code

PHPBB3-16944

phpBB/adm/style/overall_footer.html

@@ -45,6 +45,7 @@
 <script src="{T_ASSETS_PATH}/javascript/core.js?assets_version={T_ASSETS_VERSION}"></script>
 <!-- INCLUDEJS ajax.js -->
 <!-- INCLUDEJS admin.js -->
+{% INCLUDEJS T_ASSETS_PATH ~ '/iconify/iconify.min.js' %}
 
 <!-- EVENT acp_overall_footer_after -->
 {$ICONIFY_ICONS}