Add turf intersect feature for polygonal intersection

[KeyG89]

I would like to propose a new feature for turf java, namely polygonal intersection, which is as explained in the turf doc as a method that:

Takes two polygon or multi-polygon geometries and finds their polygonal intersection. If they don't intersect, returns null.

It might help on various occasions while dealing with area-specific features on Android apps, for example, intersecting camera bounds with certain polygons can make a huge deal in making area-aware functionalities.

While looking for such a solution I've encountered geok library:
https://github.com/piruin/geok - written in Kotlin, that apparently achieves this goal, so maybe it may be some kind of inspiration.

[gangding]

@allanwalkerit: I have the same request of porting turf.js' intersect function to Java. This will provide a more powerful tool than the currently available function TurfJoins

[allanwalkerit]

FAO @tobrun as discussed