feat(network-primitives): expose more fields via block response traits

[yash-atreya]

Motivation

HeaderResponse exposed very limited fields. BlockResponse doesn't expose other fields in case of WithOtherFields<Block>.

Solution

• Expose miner, gas_limit, mix_hash, difficulty in HeaderResponse. Exposing these fields helps to initialize a revm::BlockEnv like so:

BlockEnv {
    number: U256::from(block.header().number()),
    timestamp: U256::from(block.header().timestamp()),
    coinbase: block.header().miner(),
    difficulty: block.header().difficulty(),
    prevrandao: block.header().mix_hash(),
    basefee: U256::from(block.header().base_fee_per_gas().unwrap_or_default()),
    gas_limit: U256::from(block.header().gas()),
    ..Default::default()
}

• Add other_fields(&self) -> Option<OtherFields> to BlockResponse which returns None by default unless overridden.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

a few nits

[mattsse]

maybe we don't need this, I assume this could eventually be removed

[yash-atreya]

OP stack based L2s use block.difficulty for generating random values.

[yash-atreya]

But I guess block.prevrandao serves the same purpose on L2s

[mattsse]

lgtm, pending @klkvr