Remove Unnecessary Includes in Headers (#4275)

* refactor: remove unnecessary includes in headers

* fix: formatting

* chore: changelog

* fix: scrollbar

* fix: suggestions and old appbase remains

* fix: suggestion

* fix: missing Qt forward declarations

* fix: another qt include

* fix: includes for precompiled-headers=off

* Add missing `<memory>` includes

* Add missing `#pragma once`

* Fix tests

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/singletons/Fonts.cpp

@@ -1,16 +1,13 @@
 #include "singletons/Fonts.hpp"
 
-#include "BaseSettings.hpp"
+#include "Application.hpp"
 #include "debug/AssertInGuiThread.hpp"
+#include "singletons/Settings.hpp"
+#include "singletons/WindowManager.hpp"
 
 #include <QDebug>
 #include <QtGlobal>
 
-#ifdef CHATTERINO
-#    include "Application.hpp"
-#    include "singletons/WindowManager.hpp"
-#endif
-
 #ifdef Q_OS_WIN32
 #    define DEFAULT_FONT_FAMILY "Segoe UI"
 #    define DEFAULT_FONT_SIZE 10