Committee-aware attestation packing (#14245)

* initial algorithm

* ready for review

* feature flag

* typo

* review

* comment fix

* fix TestProposer_sort_DifferentCommittees

* flag usage

config/features/config.go

@@ -48,6 +48,7 @@ type Flags struct {
 	EnableDoppelGanger                  bool // EnableDoppelGanger enables doppelganger protection on startup for the validator.
 	EnableHistoricalSpaceRepresentation bool // EnableHistoricalSpaceRepresentation enables the saving of registry validators in separate buckets to save space
 	EnableBeaconRESTApi                 bool // EnableBeaconRESTApi enables experimental usage of the beacon REST API by the validator when querying a beacon node
+	EnableCommitteeAwarePacking         bool // EnableCommitteeAwarePacking TODO
 	// Logging related toggles.
 	DisableGRPCConnectionLogs bool // Disables logging when a new grpc client has connected.
 	EnableFullSSZDataLogging  bool // Enables logging for full ssz data on rejected gossip messages
@@ -254,6 +255,10 @@ func ConfigureBeaconChain(ctx *cli.Context) error {
 		logEnabled(EnableQUIC)
 		cfg.EnableQUIC = true
 	}
+	if ctx.IsSet(EnableCommitteeAwarePacking.Name) {
+		logEnabled(EnableCommitteeAwarePacking)
+		cfg.EnableCommitteeAwarePacking = true
+	}
 
 	cfg.AggregateIntervals = [3]time.Duration{aggregateFirstInterval.Value, aggregateSecondInterval.Value, aggregateThirdInterval.Value}
 	Init(cfg)