Enhancements

Fix not adding local rulesets as Clash rule-providers.
Add "nullnode" as node placeholder to export configurations without adding any real node.
Add support for using !!import in source subscription URLs.
Add support for allowInsecure and tfo argument in Trojan links.
Optimize codes.

src/templates.cpp

@@ -290,7 +290,7 @@ int renderClashScript(YAML::Node &base_rule, std::vector<ruleset_content> &rules
             }
             if(remote_path_prefix.size())
             {
-                if(isLink(rule_path) || startsWith(rule_path, "data:"))
+                if(fileExist(rule_path, true) || isLink(rule_path))
                 {
                     rule_name = std::to_string(hash_(rule_group + rule_path));
                     names[rule_name] = rule_group;
@@ -314,6 +314,7 @@ int renderClashScript(YAML::Node &base_rule, std::vector<ruleset_content> &rules
                 continue;
             }
 
+            retrieved_rules = convertRuleset(retrieved_rules, x.rule_type);
             char delimiter = getLineBreak(retrieved_rules);
 
             strStrm.clear();