Add the Qt window module as an alternative to the SDL2 module

Att the Qt window module as an alternative to the SDL2 module

Description is TBD

src/module/qt_window/mainwindow.cc

+#include "mainwindow.hh"
+
+MainWindow::MainWindow(module_qt_window_s *qt_window, QWidget *parent)
+    : QMainWindow(parent)
+{
+    qt_window->mpv_widget = new MpvWidget(qt_window->queue, qt_window->db, qt_window->reg,
+                                          &(qt_window->launched), this);
+    connect(qt_window->mpv_widget, &MpvWidget::titleChanged, this, &MainWindow::updateWindowTitle);
+    setCentralWidget(qt_window->mpv_widget);
+    setFocusPolicy(Qt::StrongFocus);
+
+    connect(this, &MainWindow::emitCloseMpv, this, &MainWindow::__closeMpv,
+            Qt::BlockingQueuedConnection);
+}
+
+void
+MainWindow::closeMpv() noexcept
+{
+    emit emitCloseMpv();
+}
+
+void
+MainWindow::__closeMpv()
+{
+    delete this;
+}