QUIC transport

[diegomrsantos]

nim-libp2p

• Merge the certificate generation and parsing PR. There are blockers related to nim-mbedtls build that need to be addressed. The problems are in the interop tests and the arm64 workflows.
• Implement certificate validation. It can be based on https://github.com/libp2p/rust-libp2p/blob/master/transports/tls/src/certificate.rs#L358.
• Make the QUIC transport code more robust. Better error handling, logs, and tests.
• This issue documents a potential integration problem with other implementations. It seems this has been fixed in the go implementation, but others remain to be checked.
• Enable QUIC in the transport interop tests
• Evaluate if QUIC support for Hole Punching needs to be implemented.

nim-quic

• Implement the full TLS handshake using nim-mbedtls as explained in https://docs.libp2p.io/concepts/transports/quic/ and https://github.com/libp2p/specs/blob/master/tls/tls.md. The ngtcp2 library has crypto helper libraries that make this integration easier, but unfortunately, it doesn't support mbedtls. It is necessary to find a way to make this integration using mbedtls.
• Implement the open issues.
• This project started as PoC and was not meant to be used in production. I don't know its robustness from a security, performance, and maintainability perspective, and it needs to be evaluated.
• Evaluate if the current tests are enough.
• Update readme.
• Make a release.