Use weiroll to batch process multiple eth_call requests in a single RPC call

[TimDaub]

• [email protected] adds weiroll support
• technically, this means that if we had an eth_call to weiroll call converter, then we could take some of the eth_calls in the queue, convert them to weiroll calls and hence save network requests
• the idea is that network requests are slow as they have roundtrip time, latency etc. and so batching network requests seems like a good idea
• potentially, if we're generically translating eth_calls to weiroll calls then we should consider natively implementing it in eth-fun
• so I may need to transfer this issue there.

[TimDaub]

closing this issue here and reopening it in eth-fun: attestate/eth-fun#51