Use unique_ptr on all ui objects from .ui files (#5511)

* Forward declare ui and use unique_ptr

* ConfigureEnhancements: use unique_ptr for ui

* Use make_unique instead of new where applicable

* Move some of the ui includes that already used unique_ptr

* main.cpp: also make use of make_unique on Config

* Address review comments

src/citra_qt/configuration/configure_graphics.cpp

@@ -13,7 +13,7 @@
 #include "video_core/renderer_opengl/post_processing_opengl.h"
 
 ConfigureGraphics::ConfigureGraphics(QWidget* parent)
-    : QWidget(parent), ui(new Ui::ConfigureGraphics) {
+    : QWidget(parent), ui(std::make_unique<Ui::ConfigureGraphics>()) {
     ui->setupUi(this);
     SetConfiguration();