Receipt handling for CIP-66 transaction

[ezdac]

Implement the correct setting of receipt fields in the applyTransaction() function.
Think about how to handle the different gas-cost denominations (CIP-64 vs CIP-66) and how downstream consumers of the receipt deal with this (external RPC API, consensus.Engine.FinalizeAndAssemble(), etc).
Additionally, how was the Receipt.BaseFee (celo specific) and Receipt.EffectiveGasPrice used for Celo denominated CIP-64 transactions and how is this different from CIP-66 transactions. Are additional fields needed and what are the consequences of changing this public API.