Qt: Add ProgressCallback implementation

src/duckstation-qt/qtprogresscallback.h

@@ -0,0 +1,31 @@
+#pragma once
+#include "common/progress_callback.h"
+#include <QtWidgets/QProgressDialog>
+
+class QtProgressCallback final : public QObject, public BaseProgressCallback
+{
+  Q_OBJECT
+
+public:
+  QtProgressCallback(QWidget* parent_widget);
+  ~QtProgressCallback();
+
+  bool IsCancelled() const override;
+
+  void SetCancellable(bool cancellable) override;
+  void SetStatusText(const char* text) override;
+  void SetProgressRange(u32 range) override;
+  void SetProgressValue(u32 value) override;
+
+  void DisplayError(const char* message) override;
+  void DisplayWarning(const char* message) override;
+  void DisplayInformation(const char* message) override;
+  void DisplayDebugMessage(const char* message) override;
+
+  void ModalError(const char* message) override;
+  bool ModalConfirmation(const char* message) override;
+  u32 ModalPrompt(const char* message, u32 num_options, ...) override;
+
+private:
+  QProgressDialog m_dialog;
+};