implemented hold keyframe and began new panel

ui/graphview.cpp

@@ -0,0 +1,13 @@
+#include "graphview.h"
+
+#include <QPainter>
+
+GraphView::GraphView(QWidget* parent) {}
+
+void GraphView::paintEvent(QPaintEvent *event) {
+    QPainter p(this);
+
+    p.setPen(Qt::white);
+
+    p.drawRect(rect());
+}