Expose ZlibCompressor/Decompressor

[adam-fowler]

This PR

• Makes ZlibCompressor/Decompressor non-copyable types (They hold mutable buffers generated by a C library). Doing this allows us to tag them as Sendable.
• Makes ZlibCompressor/Decompressor public
• Adds ByteBuffer methods that use the ZlibCompressor/Decompressor directly
• Add wrapper types that wrap the new types and conform to NIOCompressor/Decompressor to ensure we using the same code path whether we use NIO or Zlib types.
• Add tests that use new concrete types.
• Deprecate NIOCompressor/Decompressor and related functions in favour of the Zlib versions. The NIO prefixed versions are unnecessary existentials and it is preferable to use the concrete Zlib versions.

[Joannis]

Can we make this work with an AsyncSequence as in- and/or output?

[adam-fowler]

I can review some of the APIs but as the Compressor is non-copyable we have to be clearer about who owns it. So using it in an AsyncSequence is problematic. Eg I have a compressor I want to re-use, if I create an AsyncSequence that takes ownership of it there is no easy to pass it back once iteration has completed.

[Joannis]

Hmm, unfortunate.