* Move cofactor clearing to dedicated per-curve subgroups file
* Add BLS12-381 fast subgroup checks
* Implement fast cofactor clearing for BN254_snarks
* Add fast subgroup check to BN254Snarks
* add BLS12_377 optimized cofactor and subgroup functions
* Add BN254_Nogami
* Add GT-subgroup tests
* Use the new subgroup checks for Eth1 EVM precompiles
* Hash to Curve: impl expand_message_xmd
* Try to precompute part of hash to curve at compile-time
* sha256 bench - use the new hashes module
* [WIP] smoke test hash to field
* Implement hash_to_field with expected output
* unoptimized hash-to-curve G2 for BLS12-381
* Don't run sanitizer on hash to field as it uses GC-ed strings
