Add support for scrypt

[brycx]

@finfet has mentioned possibly upstreaming their scrypt implementation to Orion in finfet/kestrel#11 (comment).

I believe this would be a worthwhile addition to Orion, since the password-based key derivation functions right now are either Argon2i or PBKDF2. If one were to interpret OWASP recommendations strictly, then a user would have to choose PBKDF2, because the Argon2id variant isn't supported right now.

scrypt could serve as a great alternative to Argon2i.

[finfet]

I think this will be a great addition and it will give people access to an another scrypt implementation. I plan to make some progress on this over the next week.