Add method to divide LineString into equal chunks

[1ec5]

The lineChunk method should be ported to this library:

Divides a LineString into chunks of a specified length. If the line is shorter than the segment length then the original line is returned.

This method would be useful for sampling a geometry before passing the simplified geometry into a map matching algorithm: mapbox/mapbox-directions-swift#661 (comment).

Suggested LineString method signatures:

func dividedIntoChunks(of length: LocationDistance, reversed: Bool) -> MultiLineString

/cc @danpat @Guardiola31337

[1ec5]

mutating func divideIntoChunks(of length: LocationDistance, reversed: Bool)

I removed this suggested method signature because it isn’t possible to convert a LineString into a MultiLineString in place. However, if we add these methods to MultiLineString itself, then it would be possible.

[MaximAlien]

Tagging @mapbox/navigation-android for parity.