Add basic lua scripting capabilities (#4341)

The scripting capabilities is locked behind a cmake flag, and is not enabled by default.

Co-authored-by: nerix <nerixdev@outlook.de>
Co-authored-by: pajlada <rasmus.karlsson@pajlada.com>

src/singletons/Settings.hpp

@@ -528,6 +528,10 @@ public:
          {"d", 1},
          {"w", 1}}};
 
+    BoolSetting pluginsEnabled = {"/plugins/supportEnabled", false};
+    ChatterinoSetting<std::vector<QString>> enabledPlugins = {
+        "/plugins/enabledPlugins", {}};
+
 private:
     void updateModerationActions();
 };