Bootstrap email-editor unit tests

I also replaced using verify function by asserts, which will be removed in the higher version of phpunit.
[MAILPOET-6216]

packages/php/email-editor/tests/_support/UnitTester.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Inherited Methods
+ * @method void wantToTest($text)
+ * @method void wantTo($text)
+ * @method void execute($callable)
+ * @method void expectTo($prediction)
+ * @method void expect($prediction)
+ * @method void amGoingTo($argumentation)
+ * @method void am($role)
+ * @method void lookForwardTo($achieveValue)
+ * @method void comment($description)
+ * @method void pause()
+ *
+ * @SuppressWarnings(PHPMD)
+*/
+class UnitTester extends \Codeception\Actor
+{
+    use _generated\UnitTesterActions;
+
+    /**
+     * Define custom actions here
+     */
+}