[noise] writing a Rust sans-IO Noise protocol

[dawuud]

> Would be happy to put HFS behind a feature gate in Snow if you or anyone else is up to the task.
> 
> It looks like quininer wrote https://github.com/quininer/newhope <https://github.com/quininer/newhope>, which may at least be a good start.


Dear Jake,

I am now up to the task.
Let's do this! Post quantum crypto for all the things.
Obviously we should make it work for Khyber and New Hope both.

Cheers,
David