ISTWCMS-4210 Add dialog plugin

src/Plugin/CKEditorPlugin/DialogPlugin.php

+<?php
+
+namespace Drupal\uw_cfg_common\Plugin\CKEditorPlugin;
+
+use Drupal\ckeditor\CKEditorPluginBase;
+use Drupal\editor\Entity\Editor;
+
+/**
+ * Defines the "dialog" plugin.
+ *
+ * @CKEditorPlugin(
+ *   id = "dialog",
+ *   label = @Translation("Dialog")
+ * )
+ */
+class DialogPlugin extends CKEditorPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getConfig(Editor $editor) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getButtons() {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFile() {
+    return drupal_get_path('profile', 'uw_base_profile') . '/libraries/ckeditor-dialog/plugin.js';
+  }
+
+}