Add stl, step, etc. to recent list (#9481)

* Add stl, step, etc. to recent list

* Make configurable

* Merge branch 'main' into recent-files-pr

src/libslic3r/AppConfig.cpp

@@ -362,6 +362,10 @@ void AppConfig::set_defaults()
         set("max_recent_count", "18");
     }
 
+    if (get("recent_models").empty()) {
+        set("recent_models", "0");
+    }
+
     // if (get("staff_pick_switch").empty()) {
     //     set_bool("staff_pick_switch", false);
     // }