Add a dialog to Batch PKG Install

Dialog allows users to preview the order in which PKG's will be installed
and allows users to move items around if needed.

Because clicking "Install" on this new dialog acts as a confirmation
and user has a second chance to eyeball what is to be installed,
"Install package X?" dialogs have been removed and instead user
is only notified of success. In case of failure, batch installation
aborts with a descriptive error.

rpcs3/rpcs3qt/main_window.h

@@ -116,7 +116,7 @@ private:
 	void CreateDockWindows();
 	void EnableMenus(bool enabled);
 	void ShowTitleBars(bool show);
-	void InstallPkg(const QString& dropPath = "", bool is_bulk = false);
+	bool InstallPkg(const QString& dropPath = "", bool show_confirm = true, bool show_success = true);
 	void InstallPup(const QString& dropPath = "");
 
 	int IsValidFile(const QMimeData& md, QStringList* dropPaths = nullptr);
@@ -134,8 +134,6 @@ private:
 	QActionGroup* m_listModeActGroup = nullptr;
 	QActionGroup* m_categoryVisibleActGroup = nullptr;
 
-	QMessageBox::StandardButton m_install_bulk = QMessageBox::NoButton;
-
 	// Dockable widget frames
 	QMainWindow *m_mw = nullptr;
 	log_frame* m_logFrame = nullptr;