Move list retrieve/render to class (#15)

- array_key_exists -> key_exists

src/lib/Security.php

@@ -131,7 +131,7 @@ class Security {
      * @param bool $redirectIfAnonymous Whether to redirect the request if there is no user logged on
      */
     public static function verifyUser(SQLite3 $db, bool $redirectIfAnonymous = true): void {
-        if (array_key_exists(Key::USER_ID, $_SESSION)) return;
+        if (key_exists(Key::USER_ID, $_SESSION)) return;
 
         if (SECURITY_MODEL == self::SINGLE_USER) self::logOnSingleUser($db);