re-organize folder structure

include/aboutwidget.h

@@ -0,0 +1,18 @@
+#ifndef ABOUTWIDGET_H
+#define ABOUTWIDGET_H
+
+#include <QWidget>
+#include <QLabel>
+
+class AboutWidget : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit AboutWidget(QWidget *parent = nullptr);
+
+private:
+    void setupUI();
+};
+
+#endif // ABOUTWIDGET_H