[libc++][ranges] Implement `lazy_split_view`.

Note that this class was called just `split_view` in the original One
Ranges Proposal and was renamed to `lazy_split_view` by
[P2210](https://wg21.link/p2210

).

Co-authored-by: zoecarver <z.zoelec2@gmail.com>

Differential Revision: https://reviews.llvm.org/D107500