Compare gzip decompressors

[newsch]

With more optimization it's likely that decompressing the gzip archives will be a bottleneck.
There are a number of "parallel" implementations for gzip, but all the ones I've looked at aren't actually useful for this case.

Steps:

• Look for more implementations
• Compare decompression rates
• Compare with rust gzip crates

What I've looked at so far:

Implementation	Notes
GNU gunzip	Baseline
pigz	Moves some decompression work to separate threads, mostly single-threaded
libdeflate	Only for small files
pugz	Hypothetically ideal, novel approach, but unstable and needs to load entire file into memory
pgzip (Python)	Decompression only parallelized when compressed with same tool
pgzip (Golang)	Decompression only does single-threaded work on a separate thread

[biodranik]

Let's run it first in the current state and see real base numbers before prioritizing/digging deeper into any optimizations.