Moving requests out of execution_payload into beacon_block.body

[lucassaldanha]

Original description from #3856

Up until Electra, the CL clients would not save the full execution payload as this is not needed on the beacon state transition function. However, Electra includes new fields like withdrawal requests, deposit requests and consolidation requests that the consensus client requires in order to perform the state transition function. With the current design the consensus client would need to either: save locally the requests; or requests the payload from the EL for each time they want to execute a state transition.

The original proposal for a ExecutionPayloadEnvelope has been surpassed by moving the requests out of the Execution Payload into a new container ExecutionClientRequests, a new field in the BeaconBlockBody. This approach has a simpler design and maintains the gindex of the Execution Payload stable.

Changes

• Added one new containers: ValidatorRequests
• Updated BeaconBlockBody with requests: ValidatorRequests
• Updated all 3 request processing functions to get the requests from block.body.requests

TODO

• Review if not missing anything
• Fix all tests that need updates
• Confirm we are good on process_withdrawals

[potuz]

You need to remove the requests from the payload as well

[mkalinin]

LGTM! 👍

[ralexstokes]

this is a reasonable change!

and I agree w/ the line of thinking that got us here around pruning payloads

left two questions that I think block merge (unless im missing something)

[ensi321]

One minor comment

[ralexstokes]

lgtm!