Switch to mirrored duplicate source technique to increase performance of hover/highlight user interactions

[ryanbaumann]

Problem

Hover/Highlights can be slow to react to user input because setFilter is slow, specifically mousemove events.

Solution

The ideal solution would be to use featureState for all user interactions - which we can do for Geojson sources used in Circle, Heatmap, and Cluster layers.

Since feature id values cannot be enforced easily for Choropleth layer Vector Tile sources, instead of featureStates we can consistently use the mirrored source technique to increase hover / highlight performance. See mapbox/mapbox-gl-js#2874 (comment) for details on how this technique works.

Outcome

Better user experience interacting with and filtering data in the Mapbox Visual.

cc/ @samgehret

[ryanbaumann]

We can evaluate using the new validate: false flag for setFilter in Mapbox GL JS 0.52.0 (currently in beta) to see if it's an easier implementation to address this issue.

[ryanbaumann]

Closing in favor of #286