Pyzstd

- Upgrade zstd source code from v1.5.2 to [v1.5.4](https://github.com/facebook/zstd/releases/tag/v1.5.4). v1.5.3 is a non-public release.
- Support `pyproject.toml` build mechanism (PEP-517). Note that specifying build options in old way may be invalid, see [build commands](https://pyzstd.readthedocs.io/#build-pyzstd).
- Support "multi-phase initialization" (PEP-489) on CPython 3.11+, can work with CPython sub-interpreters in the future. Currently this build option is disabled by default.
- Add a command line interface (CLI).

- Fix `ZstdError` object can't be pickled.

- Upgrade zstd source code from v1.5.1 to [v1.5.2](https://github.com/facebook/zstd/releases/tag/v1.5.2).

- Upgrade zstd source code from v1.5.0 to [v1.5.1](https://github.com/facebook/zstd/releases/tag/v1.5.1).
- Fix `ZstdFile.write()` / `train_dict()` / `finalize_dict()` may use wrong length for some buffer protocol objects.
- Two behavior changes:
- Setting `CParameter.nbWorkers` to `1` now means "1-thread multi-threaded mode", rather than "single-threaded mode".
- If the underlying zstd library doesn't support multi-threaded compression, no longer automatically fallback to "single-threaded mode", now raise a `ZstdError` exception.
- Add a module level variable [`zstd_support_multithread`](https://pyzstd.readthedocs.io/#zstd_support_multithread).
- Add a setup.py option `--avx2`, see [build options](https://pyzstd.readthedocs.io/#build-pyzstd).

- Upgrade zstd source code from v1.4.9 to [v1.5.0](https://github.com/facebook/zstd/releases/tag/v1.5.0).
- Some improvements, no API changes.

- Add a CFFI implementation that can work with PyPy.
- Allow dynamically link to zstd library.