Fix incorrect argument count for find in template

Add managed_config_prefix to global variables in template.

src/interfaces.cpp

@@ -765,6 +765,7 @@ void readConf()
             continue;
         global_vars[x.first] = x.second;
     }
+    global_vars["managed_config_prefix"] = managed_config_prefix;
 
     ini.EnterSection("server");
     ini.GetIfExist("listen", listen_address);

src/templates.cpp

@@ -50,7 +50,7 @@ int render_template(const std::string &content, const template_args &vars, std::
         std::string data = args.at(0)->get<std::string>();
         return trim(data);
     });
-    m_callbacks.add_callback("find", 1, [](inja::Arguments &args)
+    m_callbacks.add_callback("find", 2, [](inja::Arguments &args)
     {
         std::string src = args.at(0)->get<std::string>(), target = args.at(1)->get<std::string>();
         return regFind(src, target);