Add support for cross-highlighting

[otravers]

At the moment, when doing Format > Edit Interactions in PBI Desktop, Mapbox can only be set to Filter or None. It would be great to have support for Highlight, so that the zoom level doesn't change and the boundaries of the selected area(s) are increased in contrast and/or width (maybe user-configurable) to make the selection stand out.

For reference: https://github.com/microsoft/PowerBI-visuals/blob/master/Tutorial/ProfessionalVisualGuidline.md#support-cross-filtering-when-available