feat: implement EIP-7549

[ensi321]

For illustration purpose only. Actual PR will be split into multiple chunks for easier review

General:

• Add containers & presets
• Retrieve field values from serialized electra.attestations

Beacon node:

• Modify processAttestations
• Update attesting indices parsing from electra.Attestation

p2p:

• Handle and publish new format of beacon_aggregate_and_proof and beacon_attestation
• New validation rule

Validator:

• Use MAX_ATTESTER_SLASHINGS_ELECTRA limit when constructing block body
• Sign electra.attestations and electra.aggregateAndProof
• Come up with new algo to get electra.attestations for block body in AggregatedAttestationPool
• Create valid attestation and aggregate when attesting/aggregating

Misc but important:

• Update beacon API format for attestation-related endpoints (pending cross-client discussion ethereum/beacon-APIs#445)
• Modify AggregatedAttestationPool to store new attestation format
• Modify AttestationPool to aggregate electra.attestations