Copy image to the clipboard

Add a context menu option to save an image in the timeline to the clipboard

BUG: 466478

src/clipboard.h

@@ -26,6 +26,7 @@ public:
     Q_INVOKABLE QString saveImage(QString localPath = {}) const;
 
     Q_INVOKABLE void saveText(QString message);
+    Q_INVOKABLE void setImage(const QUrl &image);
 
 private:
     QClipboard *m_clipboard;