Add attestation simulator (#4880)

* basic scaffold

* remove unnecessary ?

* check if committee cache is init

* typed ValidatorMonitor with ethspecs + store attestations within

* nits

* process unaggregated attestation

* typo

* extract in func

* add tests

* better naming

* better naming 2

* less verbose

* use same naming as validator monitor

* use attestation_simulator

* add metrics

* remove cache

* refacto flag_indices process

* add lag

* remove copying state

* clean and lint

* extract metrics

* nits

* compare prom metrics in tests

* implement lag

* nits

* nits

* add attestation simulator service

* fmt

* return beacon_chain as arc

* nit: debug

* sed s/unaggregated/unagg.//

* fmt

* fmt

* nit: remove unused comments

* increase max unaggregated attestation hashmap to 64

* nit: sed s/clone/copied//

* improve perf: remove unecessary hashmap copy

* fix flag indices comp

* start service in client builder

* remove //

* cargo fmt

* lint

* cloned keys

* fmt

* use Slot value instead of pointer

* Update beacon_node/beacon_chain/src/attestation_simulator.rs

Co-authored-by: Paul Hauner <paul@paulhauner.com>

---------

Co-authored-by: Paul Hauner <paul@paulhauner.com>

beacon_node/client/src/builder.rs

@@ -2,6 +2,7 @@ use crate::address_change_broadcast::broadcast_address_changes_at_capella;
 use crate::config::{ClientGenesis, Config as ClientConfig};
 use crate::notifier::spawn_notifier;
 use crate::Client;
+use beacon_chain::attestation_simulator::start_attestation_simulator_service;
 use beacon_chain::data_availability_checker::start_availability_cache_maintenance_service;
 use beacon_chain::otb_verification_service::start_otb_verification_service;
 use beacon_chain::proposer_prep_service::start_proposer_prep_service;
@@ -839,6 +840,10 @@ where
                 runtime_context.executor.clone(),
                 beacon_chain.clone(),
             );
+            start_attestation_simulator_service(
+                beacon_chain.task_executor.clone(),
+                beacon_chain.clone(),
+            );
         }
 
         Ok(Client {