Add triangulate property to geojsonToBinary

[felixpalmer]

Background

We have found that the geojsonToBinary function can be very slow (multiple seconds) when processing large polygons due to the triangulation done via earcut. This PR adds a new optional parameter to disable the triangulation. By defaulting to true we maintain back compatibility but enable fast processing when needed (e.g. for a realtime API).

The result is that the output data structure doesn't include the polygons.triangles property. deck.gl is able to cope with this and will perform the tesselation at render time, much like it does when rendering GeoJSON.

Changelist

• Add new parameter to geojsonToBinary
• Implementation in flat-geojson-to-binary.ts
• Doc & test update

[ibgreen]

Nice clean PR.

• It would be nice to also add a bullet to the whats-new page.
• It would be good to mention on the doc page that the new option is only available from v4.0 to avoid confusion.

I generally refer to what earcut does as polygon tesselation. Thinking that maybe the option should be called tesselate instead of triangulate.

If you need this asap, please backport to 3.4-release branch and notify @belom88 so that it makes it into the weekly patch release.

We'd probably not mention it in the 3.4 docs as it is a late patch.