Remove deprecated code

Author: thomas-kl1

app/code/Magento/Store/Model/WebsiteRepository.php

@@ -168,18 +168,6 @@ public function clean()
         $this->allLoaded = false;
     }
 
-    /**
-     * Retrieve application config.
-     *
-     * @deprecated 100.1.3 Should be lazy loaded with a proxy via the DI.
-     * @see self::$appConfig
-     * @return Config
-     */
-    private function getAppConfig(): Config
-    {
-        return $this->appConfig;
-    }
-
     /**
      * Initialize default website.
      *