Rewrite gzip component to support trailing bytes without external tool and compress with PIGZ. Addresses #476

[alchzh]

• [x] I have reviewed the OFRAK contributor guide and attest that this pull request is in accordance with it.

Rewrite gzip component to support trailing bytes without external tool.

Link to Related Issue(s)

476

python/cpython#68489

Please describe the changes in your request.

• Replaces the use of the gzip library with calls to the underlying zlib library directly, in a way that doesn't fail with trailing garbage at the end of files.
• Substantially rewrites of gzip test cases to use a common template
  • adds a test for multi member gzip files
  • the trailing bytes test actually tests the unpack

[alchzh]

Based on benchmarks of zlib module vs pigz, no benefit to using pigz for decompression, but significant benefit to using it for compression.

https://gist.github.com/alchzh/24ca62a6f87548ea2b1911c174e0ed54