Add support for more elliptic curves

[sosthene-nitrokey]

• p348 (using RustCrypto)
• p521 (using Ruscrypto)
• brainpoolP256r1 (Mechanism definition only, implementation in separate backend)
• brainpoolP384r1 (Mechanism definition only, implementation in separate backend)
• brainpoolP512r1 (Mechanism definition only, implementation in separate backend)

This PR is the upstream version of #163

[robin-nitrokey]

I noticed that the there are no client traits for the brainpool curves. No big issue for me because I don’t really like the API duplication between CryptoClient and the mechanisms. But is there a special reason for that?

Otherwise LGTM.

[sosthene-nitrokey]

Good point.

I did not add the client traits because I don't use them in opcard, so they would not end up being used anyway.
We can add them in the future if needed.