confusion between chainId and networkId in nimbus-eth1 code

[jangko]

Coincidentally, the networkId and chainId of mainnet and some of built in testnets have identical value.
This lead to misuse/mix use of them in many places and not detected by any test. They also use ordinary integer without clear distinction to prevent incorrect assignment from chainId to networkId and vice versa.

Some functions/parameter also misnomer in this area that lead to other developers(e.g. me) to believe they are the same entity but actually different.

My experiment with EIP2930 reveal this issue should be fixed before EIP2718 and EIP2930 are implemented.

Furthermore, this issue will add more confusion for the upcoming EIP2364, EIP2464, and EIP2481.

see also https://medium.com/@pedrouid/chainid-vs-networkid-how-do-they-differ-on-ethereum-eec2ed41635b