Configure multiple mev-commit chain IDs for devnet/testnet/mainnet

[shaspitz]

17864 has been the only chain ID we've been using for instances of the mev-commit chain. Now that we're nearing mainnet, we should make all contracts, clients, etc. able to handle different chain IDs for the mev-commit chain, corresponding to different environments.

For example we could keep 17864 for devnet cluster environments, and use a different chain ID for our user-facing testnet chain, and another chain ID for mainnet mev-commit chain. This is common practice to prevent txes being replayed across multiple chain instances.