feat: Implement all queries on `float::kdtree::ArchivedKdTree`. Update rkyv example

[sdd]

Rkyv example updated to ensure that we use rkyv's zero-copy mode rather than deserializing. Additionally use memmap when reading in from files. Show times to compare with and without memmap and zero-copy.

[sdd]

This addresses https://github.com/sdd/kiddo/issues/36