`sha2-asm` feature

[mempirate]

Context

This PR implements a feature for enabling the asm feature on the sha2 crate. When testing against a real world payload (generate a proof of transaction inclusion against the transactions root), these are the numbers:

• sha2-asm feature disabled:

  Transactions root: 0x3834068daa909f5553bd06299dc60ccd43fa2c24da3778dda30b6c7fc767f240, num transactions: 129
  Index to prove: 26
  Generated proof in 855.763416ms
  Verified proof in 9.708µs

• sha2-asm feature enabled:

  Transactions root: 0x3834068daa909f5553bd06299dc60ccd43fa2c24da3778dda30b6c7fc767f240, num transactions: 129
  Index to prove: 26
  Generated proof in 133.917375ms
  Verified proof in 1.917µs

Conclusion

With sha2-asm enabled, proof generation becomes around 6,5 times faster.

[ralexstokes]

linter error looks like a new issue from a nightly release -- ill go fix and then we can merge this in

[ralexstokes]

@mempirate if you rebase against main ill merge this in

[mempirate]

@ralexstokes this branch should be up to date, nothing to rebase. Maybe I misunderstood

[ralexstokes]

hmm yeah im a little confused why the linter is still failing, let me see what I can do -- maybe I just merge anyway as I don't think it will fail on main