Created middleware to cache generated QR codes

module/Core/config/dependencies.config.php

@@ -1,6 +1,7 @@
 <?php
 use Acelaya\ZsmAnnotatedServices\Factory\V3\AnnotatedFactory;
 use Shlinkio\Shlink\Core\Action;
+use Shlinkio\Shlink\Core\Middleware;
 use Shlinkio\Shlink\Core\Options\AppOptions;
 use Shlinkio\Shlink\Core\Service;
 
@@ -19,6 +20,7 @@ return [
             // Middleware
             Action\RedirectAction::class => AnnotatedFactory::class,
             Action\QrCodeAction::class => AnnotatedFactory::class,
+            Middleware\QrCodeCacheMiddleware::class => AnnotatedFactory::class,
         ],
     ],