Add support for WebRTC

[melekes]

Closes #1712

[github-actions]

twiggy diff report

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

---

 Delta Bytes │ Item
─────────────┼───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       -8624 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h005eb6fb15cc0fff
       +8624 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3a656bbd422fdc23
       -3569 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h242b1497924998e5
       +3569 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h2ebbb5d641a8626a
       +3271 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h405deb837285711d
       -3035 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hbd12f0c35a859345
        +414 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::tasks::connection_task<smoldot_light_wasm::platform::Platform>::{{closure}}>>::h900a8e11ab5b42e0
        -414 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::tasks::connection_task<smoldot_light_wasm::platform::Platform>::{{closure}}>>::hcb8e6c4550121d27
        +386 ┊ <futures_util::future::poll_fn::PollFn<F> as core::future::future::Future>::poll::h0e903a3cfb14396f
        -386 ┊ <futures_util::future::poll_fn::PollFn<F> as core::future::future::Future>::poll::h5ff4c04d24b423c7
        +370 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::tasks::multi_stream_connection_task<smoldot_light_wasm::platform::Platform>::{{closure}}>>::ha958c50f6c8aa52d
        -364 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::tasks::multi_stream_connection_task<smoldot_light_wasm::platform::Platform>::{{closure}}>>::h941e779fb63de388
        +351 ┊ connection_stream_opened
        +245 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h183c6bba4e655860
        +204 ┊ <either::Either<L,R> as core::iter::traits::iterator::Iterator>::next::h0d107db34c4571e4
        +202 ┊ alloc::raw_vec::RawVec<T,A>::grow_exact::h84bc74aebad43fe7
        +198 ┊ smoldot_light::network_service::tasks::multi_stream_connection_task::{{closure}}::{{closure}}::{{closure}}::h419d4e569fc2c096
        -197 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::update_round<smoldot_light_wasm::platform::Platform>::{{closure}}>>::h85f556d3da29148a
        +197 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light::network_service::update_round<smoldot_light_wasm::platform::Platform>::{{closure}}>>::hc3a55dd95c6249a7
        -196 ┊ smoldot_light::network_service::tasks::multi_stream_connection_task::{{closure}}::{{closure}}::{{closure}}::ha6c1306956523bc4
       +1218 ┊ ... and 32 more.
       +4311 ┊ Σ [52 Total Rows]

[tomaka]

Should be ready to merge in my opinion.

[melekes]

LGTM