Qt Charts 2.1.2

Fixed issues
------------
- [QTBUG-54914] Make OpenGL accelerated series obey series visibility
- [QTBUG-54803] Ensure the chart is drawn whenever the render node is recreated
- [QTBUG-55098] Fix partial blurriness of the gl accelerated graph
- [QTBUG-54763] Clarify QML BarSet::values documentation
- [QTBUG-53073] Fix VXYModelMapper documentation
- [QTBUG-52654] Print console warning when invalid row/column used in model mapper
- [QTBUG-52086] Fix BarSet value rounding
- [QTBUG-53949] Fix axis minimum height in case of multiple axes on same orientation
- [QTBUG-54401] Fix issues with reverse axes
    - QChart mapping functions returned unreversed values
    - Bounding regions of series were incorrect
    - Mouse events gave wrong positions
    - Chart scrolling and zooming didn't account for reversed axes
- [QTBUG-55278] Disconnect boxplot series from chart's dataset correctly
- [QTBUG-53337] Fix setting axis color properties to black for the first time
- [QTBUG-55348] Disconnect a series from ChartItem when it is removed from a chart
- Fix logarithmic axis for area chart
- [QTBUG-55431] Fix setting area series edge series after area series is shown

Fixed examples
--------------
- [QTBUG-54492] Fix resize handling in Callout example
