Added capability to configure a double click event on rows

[brfreek]

Can also implement this for cells and columns, but for our current use case rows only require double click.
It uses the React.MouseEvent to detect the number of clicks and based on that either trigger the normal onClick action or a new onDoubleClickAction.

[Andries-Smit]

I opened a double click PR for DataGrid2 :D mendix/web-widgets#776
The question would we like to align to Data Grid 1, with (double) click and selection? With a single action and a switch for double or single click. This is only useful when we can implement "listen to datasoure" in this widget too.