Added new qml module for drawing lines

include/rqt_demo_plugin/lineItem.hpp

@@ -0,0 +1,32 @@
+#pragma once
+#include <QtQuick/QQuickItem>
+#include <qchar.h>
+#include <qglobal.h>
+#include <qobjectdefs.h>
+#include <qpoint.h>
+#include <qquickitem.h>
+#include <qsgnode.h>
+
+class LineItem : public QQuickItem
+{
+    Q_OBJECT
+
+    Q_PROPERTY(QString stupid READ stupid WRITE setStupid)
+    QML_ELEMENT
+public:
+    LineItem(QQuickItem *parent = nullptr);
+    ~LineItem();
+
+    QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *) override;
+
+    QString stupid() const {return stupid_;}
+
+    void setStupid(const QString &str) {
+        stupid_ = str;
+        qDebug() << str;
+    }
+    
+
+private:
+    QString stupid_;
+};