Wiktor/Migrate to RustCrypto

[wiktor-k]

This is a continuation of #16 to see how far we can go :)

[wiktor-k]

Folks, a quick summary of what's going on:

Thanks to @jcspencer's work in #30 (that I've cherry-picked here) and a bit of message capturing code I've recorded a test session (tests/sign-and-verify.sh) and put all these requests in tests/messages (it occurred to me now that I've captured only requests, ugh, time to capture more!).

Then, I added a "roundtrip tests" thingy that takes all messages, decodes them and re-encodes and compares bytes. (The encoding part, once again, thanks to @jcspencer 🙇 ).

I think this can severely simplify the recent tests that we have. First of all putting test artifacts in tests/messages automatically tests for decode/encode cycle so it's not necessary to do it twice. Second it's not necessary to hex-encode that... I hope you don't mind @baloo 😅

And the tests now can only check if the message that's decoded has correct stuff in appropriate places which should make them a bit more readable.

[baloo]

shipit shipit

[wiktor-k]

Okay folks... I'm going to clean up the commits a bit (too many WIPs from me 😅 ) and merge it. Once in main it's easier to stabilize and check what's still missing.

Thanks for your help and patience! 👋