callbundle: balance change of user-supplied addresses

[metachris]

Allow users to submit a list of addresses they want to get the coinbase difference for as part of the simulation result.

[thegostep]

Would be best to create a new generalized rpc call for this purpose: https://github.com/flashbots/mev-geth/issues/101

method: 'eth_balanceDeltaBundle'

params: [{
    balanceDelta: [
        // This should return a uint256, for a future PR, we could add a "formatter" akin to the debug_trace*
        // JavaScript runtime environment
        { address: '0x0...', data: '0x0....' } 
    ],
    txs: [ ], // signed or unsigned txs, same as callBundle
    stateBlockNumber: 1,
    blockNumber: 1
}]

result: {
    balanceDelta: [
        { delta: 100 }
    ],
    txs: [ ... ] // normal callBundle tx return
}