Add trait for KEMs and DH functions

[popel11]

Add traits for public-key cryptography: Diffie-Hellman and Key Encapsulation Mechanism.

(sorry for that previous request, I should have thought twice before posting, and now I don't know how to undo the commits, so I'm making this new request).

[KizzyCode]

Hey, first no worries regarding your previous MR 😊

However this crate is not used anymore, and I'm not sure why I haven't archived it. Tbh I would strongly recommend against its use and take a look at https://github.com/RustCrypto. If you really depend on this crate and the new traits getting merged, please let me know and I can do that – however I think it might be better to switch to another crate instead. Sorry for the inconvenience 😕

[popel11]

I was planning to use this crate for an upcoming project, but you're right - crates aead, digest and kem will work better.
Should I close the pull request? Or leave it here? Or do you yank the crate?

[KizzyCode]

I was planning to use this crate for an upcoming project, but you're right - crates aead, digest and kem will work better.

Sounds like a good idea; I also think they will suit you – anyone tbh :D – better than this one. Please feel free to close this PR if you agree; and then I'll archive the project.