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_ui.cpp

@@ -7,7 +7,8 @@
 #include "citra_qt/uisettings.h"
 #include "ui_configure_ui.h"
 
-ConfigureUi::ConfigureUi(QWidget* parent) : QWidget(parent), ui(new Ui::ConfigureUi) {
+ConfigureUi::ConfigureUi(QWidget* parent)
+    : QWidget(parent), ui(std::make_unique<Ui::ConfigureUi>()) {
     ui->setupUi(this);
     InitializeLanguageComboBox();