Added option to change JWT expiration time called "Login expiration" in the Advanced tab

backend/appdata/default.json

@@ -50,6 +50,7 @@
       "multi_user_mode": false,
       "allow_advanced_download": false,
       "use_cookies": false,
+      "jwt_expiration": 86400, 
       "logger_level": "info"
     }
   }

backend/appdata/encrypted.json

@@ -50,6 +50,7 @@
         "multi_user_mode": false,
         "allow_advanced_download": false,
         "use_cookies": false,
+        "jwt_expiration": 86400,
         "logger_level": "info"
       }
     }