Remove extra_servers.txt configuration file and update sub_handler function for clarity

- Deleted the `extra_servers.txt` file as it was no longer needed.
- Refactored the `sub_handler` function to improve variable naming, changing `url` to `query_url` for better readability and understanding of the code's purpose.

Author: lonelam

base/_SubConfig/extra_servers.txt

@@ -194,7 +194,7 @@ pub async fn sub_handler(
     }
 
     let urls = match query.url.as_deref() {
-        Some(url) => url_decode(url).split('|').map(|s| s.to_owned()).collect(),
+        Some(query_url) => query_url.split('|').map(|s| s.to_owned()).collect(),
         None => {
             if authorized {
                 global.default_urls.clone()