Implement pectra-devnet-4 changes

[yperbasis]

https://notes.ethereum.org/@ethpandaops/pectra-devnet-4

• EIP-7251 address update: Done - Update EIP-7251: update byte code with logging ethereum/EIPs#8889
• Block body requests header update: Awaiting merge - Update EIP-7685: remove requests from block body ethereum/EIPs#8908
• Change to Engine API for requests (flattening): Awaiting merge - engine: Make execution requests a sidecar, take 2 ethereum/execution-apis#591
• Change deposits to flat encoding: Awaiting merge - Update EIP-6110: change request to flat encoding ethereum/EIPs#8856
• Change withdrawal reqs to flat encoding: Todo - Update EIP-7002: change request to flat encoding ethereum/EIPs#8855
• Change reqs hash to flat hash: Todo - Update EIP-7685: change requests hash to flat hash ethereum/EIPs#8854
• Change consolidation reqs to flat encoding: Todo - Update EIP-7685: change requests hash to flat hash ethereum/EIPs#8854

Also, awaiting release of pectra-devnet-4 tests release at ethereum/execution-spec-tests#832

[somnathb1]

Priority high here means importance, not all EIPs in the list have been merged/finalized yet for pectra-devnet-4. The issue is expected to remain open for some time till the EIPs are finalized. The code changes will be accumulated over multiple PRs referencing this issue.