ui: Showing indexing progress in windows task bar

* implemented showing indexing progress in windows taskbar button
* renamed TaskShowStatusDialog
* added "Qt5WinExtras.dll" for windows builds

src/lib_gui/qt/window/QtMainWindow.cpp

@@ -374,6 +374,21 @@ void QtMainWindow::refreshStyle()
 	setStyleSheet(utility::getStyleSheet(ResourcePaths::getGuiPath().concatenate(FilePath("main/main.css"))).c_str());
 }
 
+void QtMainWindow::setWindowsTaskbarProgress(float progress)
+{
+	m_windowsTaskbarButton.setProgress(progress);
+}
+
+void QtMainWindow::hideWindowsTaskbarProgress()
+{
+	m_windowsTaskbarButton.hideProgress();
+}
+
+void QtMainWindow::showEvent(QShowEvent* e)
+{
+	m_windowsTaskbarButton.setWindow(this);
+}
+
 void QtMainWindow::keyPressEvent(QKeyEvent* event)
 {
 	switch (event->key())