Implement Block Production

[tbenr]

https://github.com/ethereum/consensus-specs/blob/dev/specs/eip4844/validator.md#get_blobs_and_kzg_commitments

Update BlockOperationSelectorFactory::createSelector to support block creation with kzg commitments retrieved from EL via engine_getBlobsBundleV1

There is also a new dataflow: engine_getBlobsBundleV1 will return blobs that needs to be stored on db once block production is completed.

We probably need a temporary cache of BlobsSidecar that need to be persisted once block is published.

This have an implication on the multiple beacon node endpoints for a VC. The beacon node will become stateful like we currently are when we do the blinded flow when mev\builder is enabled: the beacon node creating the block will cache the blobs associated to the block. Block publication needs to be done by the same beacon node, which is the only one who have the blobs and is able to construct SignedBeaconBlockAndBlobsSidecar and publish it over the network.

• update BlockOperationSelectorFactory to call engine API getBlobsBundle to provide kzg commitments to block builder
• cache BlobsSidecar using blobs obtained from the engine API getBlobsBundle
• update block publication to construct SignedBeaconBlockAndBlobsSidecar with signed block coming from VC and cached BlobsSidecar.
• Store BlobsSidecar on db