code: protected function doGetTemplateFolders($path, $level=0)
  	{
  		$return = array();
  		$rootDir = Contao\System::getContainer()->getParameter('kernel.project_dir');
  
  		foreach (scan($rootDir . '/' . $path) as $file)
  		{
  			if (is_dir($rootDir . '/' . $path . '/' . $file))
  			{
  				$return[$path . '/' . $file] = str_repeat(' &nbsp; &nbsp; ', $level) . $file;
  				$return = array_merge($return, $this->doGetTemplateFolders($path . '/' . $file, $level+1));
  			}
  		}
  
  		return $return;
  	}
docs: Return all template folders as array
  
  @param string  $path
  @param integer $level
  
  @return array