code: public function getConfigsPath(Container $app)
      {
          static $paths = [];
          $me = get_class($this);
          if (empty($paths[$me])) {
              $subpath = $this->packOptions['configs_subpath'];
              $paths[$me] = dirname($this->getReflector()->getFileName()) . '/' . $subpath;
          }
          return $paths[$me];
      }
docs: The path of the configs.
  @see \Quazardous\Silex\Api\ConfigurablePackInterface::getConfigsPath()
  @return string