Extend snapshot parser to read mark/set/go snapshots

As a developer of the Boot from Snapshot feature, I need the bootstrap parser to read the Haskell Node NewEpochState mark/set/go snapshots. They provide the rewards calculations that are needed from three epics notably referred to as "mark", "set", and "go".

Their usage is described in the document "Shelly Era Ledger", under the Rewards Calculations chapter.