create hardcoded config per Ethereum network
currently the contract address has to be passed via command line. for testnets w/ a known contract (eg Goerli) we should create a config containing the contract address so that it can be selected with the respective chain ID, while still allowing the address to be specified via command line.

it should also contain 
- bootnodes if applicable
- chain ID 
- potentially gas limit if it's an L2