Make light clients gossip block announces to each other

[tomaka]

Close #2157
Changes are very similar to #2143

[mergify]

Automatically approving tomaka's pull requests. This auto-approval will be removed once more maintainers are active.

[github-actions]

twiggy diff report

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

---

 Delta Bytes │ Item
─────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       +4667 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3503dab5c4fb46b2
       +4327 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h91ba71e252c576f0
       -4103 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hae1309c459dd754b
       -3230 ┊ smoldot_light_base::sync_service::standalone::Task<TPlat>::process_one_verification_queue::hb7a42ee11335c269
        +477 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h0c3e2bc057ccde9d
        +415 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light_base::sync_service::standalone::start_standalone_chain<smoldot_light_wasm::platform::Platform>::{{closure}}>>::hcdc1a0177e14f448
        +408 ┊ hashbrown::raw::RawTable<T,A>::resize::h345a6b7afbbf3841
        +297 ┊ hashbrown::raw::RawTable<T,A>::rehash_in_place::h7c9f0667459c2e05
        +213 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h9bd8c70dc12a1f4f
        +193 ┊ <core::iter::adapters::copied::Copied<I> as core::iter::traits::iterator::Iterator>::fold::hcb78093b4ef1dfc3
        +193 ┊ <core::iter::adapters::copied::Copied<I> as core::iter::traits::iterator::Iterator>::fold::he17d8f74fd701fac
        +185 ┊ <hashbrown::raw::RawIterRange<T> as core::iter::traits::iterator::Iterator>::next::h00267c30f0c34f35
        +181 ┊ hashbrown::raw::RawTable<T,A>::reserve_rehash::hb0e9a76d96ce59cd
        +173 ┊ smoldot::sync::all::AllSync<TRq,TSrc,TBl>::try_add_known_block_to_source::hecf797c8b3250926
        +162 ┊ <hashbrown::raw::RawTable<T,A> as core::iter::traits::collect::IntoIterator>::into_iter::hfa35f3d60fc6e167
        +158 ┊ <hashbrown::map::HashMap<K,V,S,A> as core::iter::traits::collect::Extend<(K,V)>>::extend::h49bede24fd7e2057
        -155 ┊ core::ptr::drop_in_place<core::future::from_generator::GenFuture<smoldot_light_base::sync_service::standalone::start_standalone_chain<smoldot_light_wasm::platform::Platform>::{{closure}}>>::hf382d324639fa195
        +151 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::ha4ac36dd4aca34d4
        +144 ┊ <either::Either<L,R> as core::iter::traits::iterator::Iterator>::fold::h2a9bef3cb4f250cd
        +144 ┊ data[0]
       +2739 ┊ ... and 61 more.
      +14931 ┊ Σ [81 Total Rows]

[melekes]

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