Add pure Rust fusion CRC32 implementations

By fusing CLMUL and native CRC32 instructions, we can achieve more
throughput on platforms which have native CRC32 instruction support.

These were generated using the ‘fast-crc32’ project, then converted from
C to Rust with the help of Claude.ai.

https://github.com/corsix/fast-crc32/
https://www.corsix.org/content/fast-crc32c-4k
https://www.corsix.org/content/alternative-exposition-crc32_4k_pclmulqdq
https://dougallj.wordpress.com/2022/05/22/faster-crc32-on-the-apple-m1/

Author: onethumb