Caplin: Inclusion of VoluntaryExits, AttesterSlashings, `Proposer…

…Slashing`s, `BlsExecutionToChange`s and `Attestation`s into block production (#10071)

This PR add operations inclusion.
## Normal operations

* BlsExecutionChange
* VoluntaryExit
* Slashings

Each of these operations blacklist the index they work on so we do not
have repeating indices for the same operations twice. we assume all
signatures are pre-validated and just see if it is a good time to
produce a block with them (by looking at their slot)
## Aggregated Attestations

There is a lot of trash attestations on the network so we separate our
algorithm in 3 steps:

### Eligibility

We iterate over the entire pool of accumulated attestations and filter
out all attestations who cannot be included at the current slot, and
compute their expected reward. (filter out if 0).

### Ranking

We rank the `Attestation`s by their expected reward (we just sort the
array of candidates) by expected reward in ascending order.

### Filtering by superset

We may have some supersets left-over, filter attestation which ends up
being supersets of other. this process is done from highest reward down
to lowest reward.

cl/aggregation/pool_impl.go

@@ -47,11 +47,6 @@ func NewAggregationPool(
 }
 
 func (p *aggregationPoolImpl) AddAttestation(inAtt *solid.Attestation) error {
-	// check if it's single attestation
-	if utils.BitsOnCount(inAtt.AggregationBits()) != 1 {
-		return fmt.Errorf("exactly one aggregation bit should be set")
-	}
-
 	// use hash of attestation data as key
 	hashRoot, err := inAtt.AttestantionData().HashSSZ()
 	if err != nil {