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/Application.hpp

@@ -20,6 +20,9 @@ class HotkeyController;
 class IUserDataController;
 class UserDataController;
 class SoundController;
+#ifdef CHATTERINO_HAVE_PLUGINS
+class PluginController;
+#endif
 
 class Theme;
 class WindowManager;
@@ -95,6 +98,10 @@ public:
     UserDataController *const userData{};
     SoundController *const sound{};
 
+#ifdef CHATTERINO_HAVE_PLUGINS
+    PluginController *const plugins{};
+#endif
+
     /*[[deprecated]]*/ Logging *const logging{};
 
     Theme *getThemes() override