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/multiplayer/lobby.cpp

@@ -18,6 +18,7 @@
 #include "core/hle/service/cfg/cfg.h"
 #include "core/settings.h"
 #include "network/network.h"
+#include "ui_lobby.h"
 #ifdef ENABLE_WEB_SERVICE
 #include "web_service/web_backend.h"
 #endif
@@ -81,6 +82,8 @@ Lobby::Lobby(QWidget* parent, QStandardItemModel* list,
     RefreshLobby();
 }
 
+Lobby::~Lobby() = default;
+
 void Lobby::UpdateGameList(QStandardItemModel* list) {
     game_list->clear();
     for (int i = 0; i < list->rowCount(); i++) {