Remove HTMLToMarkdown dependency

app/Core/Base.php

@@ -113,7 +113,6 @@ use Pimple\Container;
  * @property \Kanboard\Model\UserMetadata                               $userMetadata
  * @property \Kanboard\Model\Webhook                                    $webhook
  * @property \Psr\Log\LoggerInterface                                   $logger
- * @property \League\HTMLToMarkdown\HtmlConverter                       $htmlConverter
  * @property \PicoDb\Database                                           $db
  * @property \Symfony\Component\EventDispatcher\EventDispatcher         $dispatcher
  */

app/ServiceProvider/ClassProvider.php

@@ -4,7 +4,6 @@ namespace Kanboard\ServiceProvider;
 
 use Pimple\Container;
 use Pimple\ServiceProviderInterface;
-use League\HTMLToMarkdown\HtmlConverter;
 use Kanboard\Core\Mail\Client as EmailClient;
 use Kanboard\Core\ObjectStorage\FileStorage;
 use Kanboard\Core\Paginator;
@@ -133,10 +132,6 @@ class ClassProvider implements ServiceProviderInterface
             return new HttpClient($c);
         };
 
-        $container['htmlConverter'] = function () {
-            return new HtmlConverter(array('strip_tags' => true));
-        };
-
         $container['objectStorage'] = function () {
             return new FileStorage(FILES_DIR);
         };