Switch to fork of ed448

[StackOverflowExcept1on]

There is fork that also has no_std support, fixed warnings, etc: https://github.com/mikelodder7/Ed448-Goldilocks

[conradoplg]

I understand the desire but we'd like to avoid pointing to less popular forks (and the original crate was already not too mainstream). Ideally crate-crypto/Ed448-Goldilocks#35 would be the best for us.

I'll leave this open while we consider the options, thanks!

[StackOverflowExcept1on]

I don't know what needs to happen for https://github.com/crate-crypto/Ed448-Goldilocks to become part of RustCrypto... They have a lot of warnings when building project, some things are not fully implemented. Even if it becomes RustCrypto, the API will probably be different.