Add support for post-London-hardfork endpoints

[i-norden]

• eth_createAccessList
• eth_feeHistory (https://github.com/ethereum/go-ethereum/blob/master/internal/ethapi/api.go#L90)
• eth_estimateGas
• eth_gasPrice
• eth_maxPriorityFeePerGas

[i-norden]

Do fall through support to proxy geth node first

[AFDudley]

The goal is to support helios
https://github.com/a16z/helios
https://a16zcrypto.com/building-helios-ethereum-light-client/

[AFDudley]

Ultimately, I expect it's for both, but we shouldn't use client names in public repos.

[AFDudley]

@i-norden Please close if completed.

[i-norden]

@AFDudley hasn't been completed, but not sure if we still want/need to do this. Watchers do not use these endpoints, this task was related to using ipld-eth-server as a general geth RPC replacement back when we were toying with the RPC as a service ideas