feat: blake3_2to1AsU8a, add 2-to-1 blake3 Hash Function

[jonathanxuu]

feat(blake32to1AsU8a): add 2-to-1 blake3 Hash Function

This function offers a new 2-to-1 blake3 function, which do padding and iterative blake3 hash as described below:

• If bitLength is not 256 by default, this function will get the same result as blake3AsU8a from @zcloak/crypto.
• If bitLength is 256, then this function will do the following things:
  • If the Uint8Array input's length is less than 32, we will padding it to 32 bytes, and will not perform blake3.
  • If the Uint8Array input's length is 33-64 bytes, we will padding it to 64 bytes, and do one-time blake3.
  • If the Uint8Array input's length is 64-96 bytes, we will padding it to 96 bytes, and do blake3 for the first 64 bytes, and generate a 32-byte result; Then, concat the '32-bytes hash result' with the remain 32 bytes, do another blake3;

So, this function will automatically do padding and iterative blake3 hash for the Uint8Array input.