Replace old qa-util-* files with stubs

qa-include/qa-external-users-wp.php

+<?php
+/**
+ * @deprecated This file is deprecated from Q2A 1.7; use the below file instead.
+ */
+
+require_once 'util/external-users-wp.php';

qa-include/qa-util-image.php

+<?php
+/**
+ * @deprecated This file is deprecated from Q2A 1.7; use the below file instead.
+ */
+
+require_once 'util/image.php';

qa-include/qa-util-sort.php

+<?php
+/**
+ * @deprecated This file is deprecated from Q2A 1.7; use the below file instead.
+ */
+
+require_once 'util/sort.php';

qa-include/qa-util-string.php

+<?php
+/**
+ * @deprecated This file is deprecated from Q2A 1.7; use the below file instead.
+ */
+
+require_once 'util/string.php';