Add BLAKE3 support

[aumetra]

Closes #173

This PR adds support for using the BLAKE3 hash function as part of a Noise connection.
Unfortunately I'm not sure if there are any test vectors for it available.

But yeah, this adds a new hash state enum variant for BLAKE3 and adds support for it to the default provider.

[aumetra]

(sorry for the reformatting btw, VSCode config doing stupid stuff. I can revert it if wanted)

[mcginty]

Hey @aumetra thanks for the PR, and I'm interested in getting this into snow!

[nazar-pc]

Would be nice to change these to trait constants once breaking changes are made in the library:

Suggested change

	fn name(&self) -> &'static str {
	"BLAKE3"
	}
	fn block_len(&self) -> usize {
	blake3::BLOCK_LEN
	}
	fn hash_len(&self) -> usize {
	blake3::OUT_LEN
	}
	const NAME: &'static str = "BLAKE3";
	const BLOCK_LEN: usize = blake3::BLOCK_LEN;
	const HASH_LEN: usize = blake3::OUT_LEN;