DAR-330: Automated tests for creating a board with Mediawiki template in description

* added <code>templateUrl</code> to <code>URLsContent</code>,
* added <code>verifyBoardDescription()</code> to <code>ForumBoardPageObject</code>,
* added <code>createNewTemplate</code> to <code>ForumPageObject</code>,
* added <code>typeInTemplateContent</code> to <code>WikiArticleEditMode</code>,
* added <code>createNewArticle</code> and <code>createNewTemplate</code> to <code>WikiArticlePageObject</code>,
* finally created <code>testTemplatesInBoardDescription</code> test.