Added ErrorHandler package dependency and remove local files

config/config.php

@@ -1,4 +1,5 @@
 <?php
+use Acelaya\ExpressiveErrorHandler\ConfigProvider as ErrorHandlerProvider;
 use Shlinkio\Shlink\CLI;
 use Shlinkio\Shlink\Common;
 use Shlinkio\Shlink\Core;
@@ -16,6 +17,7 @@ use Zend\Expressive\ConfigManager\ZendConfigProvider;
  */
 
 return (new ConfigManager([
+    ErrorHandlerProvider::class,
     Common\ConfigProvider::class,
     Core\ConfigProvider::class,
     CLI\ConfigProvider::class,