UI ember engines (#6718)

Adds replication engine and core in-repo addon

ui/lib/core/addon/components/popup-menu.js

@@ -0,0 +1,21 @@
+import Component from '@ember/component';
+import layout from '../templates/components/popup-menu';
+
+/**
+ * @module PopupMenu
+ * `PopupMenu` displays a button that when pressed will toggle open a menu that is yielded in the content
+ * block.
+ *
+ * @example
+ * ```js
+ * <PopupMenu><nav class="menu"> <ul class="menu-list"> <li class="action"> <button type="button">A menu!</button> </li> </ul> </nav></PopupMenu>
+ * ```
+ *
+ * @param contentClass=''{String} A class that will be applied to the yielded content of the popup.
+ */
+
+export default Component.extend({
+  layout,
+  contentClass: '',
+  tagName: 'span',
+});