OP specific beacon consensus crate

[emhane]

Describe the feature

A new crate op-beacon-core should be made with a new type OptimismBeaconConsensus. The crate should live alongside the beacon-core crate. The type OptimismBeaconConsensus should impl reth_interfaces::consensus::Consensus trait. The goal with this is to remove the optimism feature from the beacon-core consensus crate.

How this new type should be plugged into the node, needs design. Possibly by replacing usage of the BeaconConsensus type with a Consensus trait object. However since this requires a lot of changes, for the scope of this PR, let's just bring either type into scope with a feature gate here

reth/crates/consensus/beacon/src/lib.rs

Line 11 in a265465

pub use reth_beacon_consensus_core::BeaconConsensus;

as such

#[cfg(not(feature = "optimism"))]
pub use reth_beacon_consensus_core::BeaconConsensus;
#[cfg(feature = "optimism")]
pub use reth_beacon_consensus_core::OptimismBeaconConsensus;

Additional context

No response

[rupam-04]

Will OptimismBeaconConsensus be a struct?