Migrate @turf/geojson-rbush to TypeScript

[mfedderly]

There's an interesting part of this change where instead of overriding the rbush object, we wrap it with our own class. This happens to improve perf for me by a little bit, I assume because of still needing to call the rbush.prototype.x methods? I think this is safe to do because we were explicitly defining the geojson version of the rbush interface in index.d.ts, and still adhere to that contract.

// before
rbush.points x 7,847,392 ops/sec ±0.48% (93 runs sampled)
rbush.polygons x 7,917,042 ops/sec ±0.24% (96 runs sampled)
search.points x 23,960,690 ops/sec ±0.20% (97 runs sampled)
search.polygons x 23,708,835 ops/sec ±0.23% (98 runs sampled)

// after
rbush.points x 10,725,369 ops/sec ±0.36% (94 runs sampled)
rbush.polygons x 10,858,871 ops/sec ±0.24% (97 runs sampled)
search.points x 25,365,964 ops/sec ±0.39% (100 runs sampled)
search.polygons x 26,213,881 ops/sec ±0.25% (99 runs sampled)