Considerably clean up the Yamux implementation

[tomaka]

This PR does a clean-up pass on the Yamux implementation, fixing many issues.

Can be reviewed commit by commit.

A ton of tests have been added, caches have been added (that should lead to better performances if there are a lot of substreams), and a couple of bugs fixed.

[github-actions]

twiggy diff report

Difference in .wasm size before and after this pull request.

---

 Delta Bytes │ Item
─────────────┼────────────────────────────────────────────────────────────────────────────────────────────────
       +3389 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::incoming_data::hbec2442590fd1b5e
       -3097 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::incoming_data::he1af0535c3421d38
       -2483 ┊ smoldot::libp2p::connection::yamux::ExtractOut<T>::extract_next::h63813046158f7ee2
       +2133 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::extract_next::h465027d23d97872e
        +979 ┊ hashbrown::raw::RawTable<T,A>::reserve_rehash::h2e6f1c7a8087b60c
        +664 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::new::h96318b718c0cf79b
        +564 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::reset::h1f65e245fde4ea1a
        -531 ┊ alloc::collections::vec_deque::VecDeque<T,A>::wrap_copy::hae8d5fcf55547b7b
        +501 ┊ <alloc::collections::vec_deque::VecDeque<T,A> as core::cmp::PartialEq>::eq::h1dd1dea36f48f671
        -486 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::open_substream::ha10e044a578140cd
        -454 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::accept_pending_substream::h28d9e37b6ac6e60c
        -409 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::queue_data_frame_header::h267b1d76a0f7d24e
        -401 ┊ smoldot::libp2p::connection::yamux::SubstreamMut<T>::reset::h8c6466aca3888c37
        -391 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::new::h06e250ba221135ec
        -378 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::queue_window_size_frame_header::h67391e1fa5ea560f
        -375 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::reject_pending_substream::hc0d0ca02e0a76273
        +327 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::accept_pending_substream::h74493668e5525915
        +323 ┊ smoldot::libp2p::connection::yamux::header::encode::h16cbec4dab922805
        +305 ┊ smoldot::libp2p::connection::yamux::write_queue::WriteQueue::extract_some::hb165d0945e5add14
        -297 ┊ smoldot::libp2p::connection::yamux::Yamux<T>::queue_ping_request_header::hb9f2001c8b8d4f21
       +1807 ┊ ... and 154 more.
       +4917 ┊ Σ [174 Total Rows]

[tomaka]

This big pull request is now ready. I've finished cleaning everything, and I believe that the code is now production-grade.

[tomaka]

Nothing wrong has been detected after one hour of fuzzing.