Add rpc functions
// eth_getERC20Balance returns the amount of ERC20 tokens for the given address in the state of the chain.
// eth_getAllERC20Balances returns the amount of ERC20 tokens for the given address in the state of the chain.
// eth_getERC20Informations returns the name, symbol, total supply and decimals of the ERC20 token at the given address.
// eth_getContractType returns the type of the contract at the given address.