engine: extract execution requests from payload

[rkrasiuk]

Description

Follow up on ethereum/consensus-specs#3875:

• define ExecutionRequestsV1
• remove requests field from ExecutionPayloadV4
• add requests field to ExecutionPayloadBodyV2
• add executionRequests parameter to engine_newPayloadV4
• add requests field to engine_getPayloadV4
• update requirements for engine_getPayloadBodiesByHashV1 and engine_getPayloadBodiesByRangeV2

[ralexstokes]

awesome, thank you!

I think we are missing a change to engine_getPayloadV4 as well

the result object also needs the execution_requests, either in the payload type, or as a sibling property like you did for engine_newPayloadV4

[ralexstokes]

#577 takes the approach to just include the execution_requests in the ExecutionPayloadV4 type, which generally has support from the recent ACD discussions around that change

[rkrasiuk]

@ralexstokes updated engine_getPayloadV4

[rkrasiuk]

@ralexstokes when are we going to make decision around #577? also, seems like it needs to be rebased on top of this PR to extract requests from ExecutionPayloadV4

[ralexstokes]

@rkrasiuk hopefully on ACDC tomorrow! (ethereum/pm#1154)

although what I meant is that if we go with the approach in #577 we will want to change this PR to reflect that, instead of changing #577

if we keep this PR like it is now, we can remove ExecutionPayloadV4 as currently it has the same definition as ExecutionPayloadV3