Support for Ed(X)448

[olegbespalov]

What?

Even though original WebCrypto API doesn't include support of the X448 and Ed448, some of webcrypto implementation does w3c/webcrypto#362

Even WebPlatfrom test suit tests this support, which led us to patch https://github.com/grafana/xk6-webcrypto/blob/main/webcrypto/tests/wpt-patches/WebCryptoAPI__generateKey__failures.js.patch

Draft can be found https://wicg.github.io/webcrypto-secure-curves/

From the Golang's perspective, support it's not so great like #93 since out of the box there is no support in standard library and not expected in the near future golang/go#29390

In theory, we could use third-party https://github.com/cloudflare/circl which has support of the X448 and Ed448

Why?

Having support of X448 and Ed448 expands usage case for our implementation.