Deterministic secure random generation

[kirelagin]

Provide functions for generating cryptographically secure random data from a seed. Namely:

• A function that takes a seed and returns a sized byte array with random data.
• And infinite stream (streamly, etc.) of random data.

Libsodium pretty much has this implemented as randombytes_buf_deterministic (https://libsodium.gitbook.io/doc/generating_random_data), but, I think, it might be better to reimplement it in Haskell to share the code with the streaming one.