Implement PEP 784 - Adding Zstandard to the Python standard library

[emmatyping]

Feature or enhancement

This is a tracking issue for implementing PEP 784. See the PEP text for more details.

Since the diff is significant (~10k lines) I wanted to split up the PRs a bit.

Implementation Plan:

• Add compression module just re-exporting existing compression modules. Move the _compression module.
• Add _zstd native module with Unix build config
• Add Windows build config for _zstd (blocked on adding libzstd to cpython-source-deps) and SBOM config.
• Add zstd Python module with tests
• Add documentation for zstd and add NEWS/What's New sections

Linked PRs

• gh-132983: Introduce compression package and move _compression module #133018
• gh-132983: Introduce _zstd bindings module #133027
• gh-132983: Install compression package contents #133063
• gh-132983: make compression._common a full-fledged package #133076
• gh-132983: Convert compression._common to a package #133086
• gh-132983: [DRAFT] Test _zstd code with Python test suite #133185

[picnixz]

It's something I should have asked on discourse, but is compression the final name of the public module? I see in the PEP that we want to mimic hashlib.algorithms_guaranteed as well and one way to mitigate the name shadowing is to actually use compressionlib as the name (we have hashlib, annotationlib, and we could have compressionlib as well; I also think compressionlib is a less likely name to be chosen but it's not the best one as well). Feel free to ignore this question as the PEP has been accepted.

[emmatyping]

It's something I should have asked on discourse, but is compression the final name of the public module?

Yes, the decision was to use compression. A search of Github code showed that it was used very infrequently. Literally one in a million files https://discuss.python.org/t/pep-784-adding-zstandard-to-the-standard-library/87377/66