Fastcdc

Added
- mzr: add `AsyncStreamCDC` for asynchronous streaming support
- cdata: add features `futures` and `tokio` to enable `AsyncStreamCDC`

Changed
- LokyinZHAO: fix: `size_hint()` returns estimated number of remaining chunks

Changed
- **Breaking:** Removed unnecessary use of `Box` from `StreamCDC` in `v2016` and `v2020`.
- *Should have made this version to be **4.0** but failed to notice the breaking change until after releasing two more updates.*

Added
- nagy: support conversion to `std::io::Error` in streaming chunkers
Fixed
- ariel-miculas: doc: fix year in `fastcdc::v2020`

Changed
- **Breaking:** moved ronomon FastCDC implementation into `ronomon` module.
What was `fastcdc::FastCDC::new()` is now `fastcdc::ronomon::FastCDC::new()`.
- flokli: remove `mut` from `&self` in `cut()` as it does not need to be mutable.
Added
- Canonical implementation of FastCDC from 2016 paper in `v2016` module.
- Canonical implementation of FastCDC from 2020 paper in `v2020` module.
- `Normalization` enum to set the normalized chunking for `v2016` and `v2020` chunkers.
- `StreamCDC`, streaming version of `FastCDC`, in `v2016` and `v2020` modules.

Added
- **Breaking:** dristic: expose hash on chunk struct.