libsodiumized version of `XK_25519_ChaChaPoly_BLAKE2b` extracted from
https://github.com/Inria-Prosecco/noise-star
git revision `38ad46c4e1adc048f8b9002c2265a96b961eb702`

karmel directory contains the necessary includes
https://github.com/project-everest/hacl-star
git version `e5620ceb7c8a4996520d693f597872806dc0a1d3`

see noise-star.patch for all changes
