Move proof verification logic to the sidecar

[thedevbirb]

When the builder submits a bid with proofs of transaction inclusion, the relay propagates them and they're verified inside our mev-boost fork. However, since the sidecar is the entrypoint from the builder api and a proxy for mev-boost it makes sense to move proof verification there, and keep the mev-boost fork as light as possible.

[mempirate]

Will leave the issue open but remove it from milestone as we will not do this for the first version. Otherwise bolt-boost cannot really be used as a standalone builder constraint mechanism since it doesn't even verify the proofs.

[merklefruit]

The reason we verify proofs in mev-boost is because we might otherwise pick a best_bid that has invalid proofs and send it to the sidecar. Closing this issue for now.