[MEV boost\Builder] Builder spec 0.2.0 support

[tbenr]

Description

we want to support version 0.2.0 and . More info here:
https://github.com/ethereum/builder-specs/releases/tag/v0.2.0

https://ethereum.github.io/builder-specs/

general flow requirements

• track builder availability status (builder_status)
• implement parallel calls to builder_getHeaderV1 and engine_getPayload with fallback handling (error or timeout)
  • should be able to transparently handle the builder_getPayloadV1 with the payload returned by engine_getPayload.
• must always use local execution engine if merge isn't completed (non-default execution payload finalized)

Execution API Clients:

• separate builder_ api from execution_ api clients (migrate builder_ to ExecutionBuilderClient)
• generic rest api client
  • implement builder_status
  • implement builder_registerValidatorV1
  • update builder_getPayloadHeaderV1 to builder_getHeaderV1
  • update builder_proposeBlindedBlockV1 to builder_getPayloadV1

ExecutionEngineChannel:

• make executionengine channel more generic (rename to ExecutionLayerChannel).
  • Will to expose engine_, builder_ and some eth1_ endpoints via two separate jsonrpc clients
  • analyze the the option to make the ExecutionLayerManagerImpl less a simple proxy for api calls and being responsible for the fallback logic. It could abstract away all the "general flow requirements".
• implement BuilderBid validations #5610

ExecutionEngineService:

• let the service poll builder_status to track builder flow availability

CLI and configuration

• introduce new eb-endpoint (execution builder)
• update --Xvalidators-proposer-mev-boost-enabled -> --Xvalidators-registration-default-enabled. #5638
• --Xvalidators-registration-default-gas-limit (default value 30000000 mainnet) #5639
• update proposer_config json with validator registration info #5640

Beacon Rest API:

• support for validator registration (ref: Add register_validator endpoint ethereum/beacon-APIs#209) in register_validator API. Must call builder_registerValidator.

Validator Client:

• support for validator registration in VC #5596
• [MEV Boost\Builder] Retrieve the feeRecipient for a validator registration #5636
• [MEV Boost\Builder] Retrieve the gasLimit and use the enabled flag for validator registration #5637
• [MEV Boost\Builder] ValidatorRegistration signature - web3signer integration #5644

Beacon Node:

• change block proposal flow to integrate builder_ (might be easy if ExecutionEngineChannel will be responsible for most of the work)

Latest Spec changes

• migrate builder_registerValidator to accept an array of registrations #5595
• Builder API messages must be signed with domain obtained by compute_domain(DOMAIN_APPLICATION_BUILDER) #5613
• [MEV Boost\Builder] Handle no header available builder response #5873

Bugfix - Improvements

• [MEV Boost\Builder] Validator Registration logs a warning when validator is not yet known by the beacon chain (pre deposit processing) #5716
• [MEV Boost\Builder] Prune Old Cached Validator Registrations #5712
• [MEV Boost\Builder] check MEV rewards #5734
• [MEV Boost\Builder] Response Body not closed (OkHttp) #5756
• [MEV Boost\Builder] /eth/v1/validator/register_validator beacon node API returns 400 when downstream builder API fails with 502 #5880

Monitoring/Logging

• [MEV Boost\Builder] Add BuilderBid logging #5710
• [MEV Boost\Builder] Add Builder Specific Metrics #5711
• [MEV Boost\Builder] May be able to report the rewards we were paid from MEV at end of block duty #5654