* electra attestation updates
In Electra, we have two attestation formats: on-chain and on-network -
the former combines all committees of a slot in a single committee bit
list.
This PR makes a number of cleanups to move towards fixing this -
attestation packing however still needs to be fixed as it currently
creates attestations with a single committee only which is very
inefficient.
* more attestations in the blocks
* signing and aggregation fixes
* tool fix
* test, import
045c4cf185