Colormap with QtCharts

Suggestion is to add the possibility to create colormaps with QtCharts.

It's possible to do it with Qt Data Visualization:
http://doc.qt.io/QtDataVisualization/qtdatavisualization-qmlspectrogram-example.html
But QAbstract3DGraph inherited classes and those classes needed to manage the associated data are more time-consuming and memory-consuming than QAbstractSeries related classes.

For real time applications, it would be nice to have an easy way of representing 2D color maps with Qt Charts.