Enhancements

Fix potential segmentation fault error due to some incorrect copy assignments.
Fix potential crash due to incorrect usage of cURL library.
Fix potential memory leak causing memory usage to be too high.
Add /qx-rewrite and /qx-script interface to add device ID to scripts for some version of Quantumult X.
Add policy-path parsing support for /surge2clash interface.
Add interval/strict options support for managed config.
Add filename option for setting file name when downloading exported subscriptions.
Optimize codes.

src/multithread.cpp

@@ -35,7 +35,7 @@ string_array safe_get_times()
 YAML::Node safe_get_clash_base()
 {
     guarded_mutex guard(clash_base_mutex);
-    return clash_base;
+    return YAML::Clone(clash_base);
 }
 
 INIReader safe_get_mellow_base()