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/subexport.h

@@ -32,6 +32,7 @@ struct extra_settings
     bool filter_deprecated = false;
     std::string surge_ssr_path;
     std::string managed_config_prefix;
+    std::string quanx_dev_id;
 };
 
 void rulesetToClash(YAML::Node &base_rule, std::vector<ruleset_content> &ruleset_content_array, bool overwrite_original_rules);