Replace compress/gzip with pgzip

[thebsdbox]

Expected Behaviour

The pgzip library implemented "parallel" gzip, this would be useful where image2disk or oci2disk hit areas of compressed data.. it wont speed up writing actual data to disk. -> https://github.com/klauspost/pgzip

Current Behaviour

We decompress in a single stream, this should decompress multiple chunks in parallel.

Possible Solution

Steps to Reproduce (for bugs)

Context

Your Environment

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