* Remove use of ethers_core::RlpStream
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into remove_use_of_ethers_core
* Remove old code
* Simplify keccak call
* Remove unused package
* Merge branch 'unstable' of https://github.com/ethDreamer/lighthouse into remove_use_of_ethers_core
* Merge branch 'unstable' into remove_use_of_ethers_core
* Run clippy
* Merge branch 'remove_use_of_ethers_core' of https://github.com/dospore/lighthouse into remove_use_of_ethers_core
* Check all cargo fmt
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into remove_use_of_ethers_core
* Revert lock
* Merge branch 'unstable' of https://github.com/sigp/lighthouse into remove_use_of_ethers_core
* introduce a shim to convert between the two u256 types
* move alloy to wrokspace
* align alloy versions
* update
* update web3signer test certs
* Revert "update web3signer test certs"
This reverts commit effd5910ad.
* Consolidate alloy versions
* Delete empty file
## Issue Addressed
Recent discussions with other client devs about optimistic sync have revealed a conceptual issue with the optimisation implemented in #3738. In designing that feature I failed to consider that the execution node checks the `blockHash` of the execution payload before responding with `SYNCING`, and that omitting this check entirely results in a degradation of the full node's validation. A node omitting the `blockHash` checks could be tricked by a supermajority of validators into following an invalid chain, something which is ordinarily impossible.
## Proposed Changes
I've added verification of the `payload.block_hash` in Lighthouse. In case of failure we log a warning and fall back to verifying the payload with the execution client.
I've used our existing dependency on `ethers_core` for RLP support, and a new dependency on Parity's `triehash` crate for the Merkle patricia trie. Although the `triehash` crate is currently unmaintained it seems like our best option at the moment (it is also used by Reth, and requires vastly less boilerplate than Parity's generic `trie-root` library).
Block hash verification is pretty quick, about 500us per block on my machine (mainnet).
The optimistic finalized sync feature can be disabled using `--disable-optimistic-finalized-sync` which forces full verification with the EL.
## Additional Info
This PR also introduces a new dependency on our [`metastruct`](https://github.com/sigp/metastruct) library, which was perfectly suited to the RLP serialization method. There will likely be changes as `metastruct` grows, but I think this is a good way to start dogfooding it.
I took inspiration from some Parity and Reth code while writing this, and have preserved the relevant license headers on the files containing code that was copied and modified.
