Ed25519 builtins for Haskell

[dolio]

This PR implements the Ed25519 builtins for #4709 in the Haskell interpreter.

I added a simple transcript that signs some bytes and verifies the signature. The secret/public keys are just an arbitrary pair that I generated for the test (despite the implementation only checking that the keys have the right length, you can't just use arbitrary byte strings).

I figured this was the more important part of the feature request, so the racket implementation is on hold until someone else gets to it, or I finish fixing the base tests on racket.

[aryairani]

We'll also need to get the two functions and the type added to base.

[aryairani]

Needs one more trunk merge and rerun transcripts due to a different merge to trunk just now. I’ll try to get to it if you don’t have it handy.

[etorreborre]

@dolio @aryairani pending the implementation of #4709 for RSA, would it be possible to do the same for RSA signatures?

[aryairani]

@etorreborre "the same" meaning... adding a test for verifying RSA signatures?

Edit: Oh, meaning adding builtins for RSA signatures

[etorreborre]

Yes, exactly.