Wesolowski and Pietrzak VDF Proof for RSW timelocks

[Rjected]

Is your feature request related to a problem? Please describe.
Currently we have timelock puzzles in the crypto package, but we can very easily create a VDF interface, and implement the Wesolowski/Pietrzak proofs for rsw, and then we'll have a VDF implementation.

Describe the solution you'd like
An implementation of https://eprint.iacr.org/2018/623, https://eprint.iacr.org/2018/627 for what we've built in rsw and an abstract VDF interface in the crypto package.

The hope is to get this as fast as possible verification wise, so using the Rjected/gmp fork of ncw/gmp would be a good idea.

Describe alternatives you've considered
There are also VDF proofs for iterated hashing, but those involve snarks and iterated-hashing as timelock puzzles aren't really that useful, since there's no trapdoor. It's better to add to what we've already written.