* Fix doppelganger protection reorders validator indices in response issue.
* Add chronos metrics endpoint to nimbus REST API.
* Doppelganger protection now works on duties not on attestations.
Improve logging for doppelganger and indices.
* Improve doppelganger and indices logging.
* Add number of validators to logs.
* Move logging dumps from `debug` to `trace` level.
* Keymanager API for the validator client
* Properly treat the 'description' field as optional when loading Keystores
* Spec-compliant serialization of the slashing data in Keymanager's DeleteKeys response ()
Fixes#3940Fixes#3964Closes#3884 by adding test
Other changes:
* logtrace can now verify sync committee messages and contributions
* Many unnecessary use of pairs() have been removed for consistency
* Map 40x BN response codes to BeaconNodeStatus.Incompatible in the VC