Enhance ledger state snapshot converter command in client CLI

[jpraynaud]

Why

We want to enhance the ledger snapshot converter command of the client CLI.

What

Make the --cardano-network parameter optional (with automatic computation) and support conversion of the most recent snapshot.

How

• Automatically detect the Cardano network from the protocolMagicId file:
  • When the --cardano-network is not set
  • Deprecate the usage of the parameter
• Convert the most recent ledger state snapshot:
  • Select the latest snapshot at first
  • Fallback on an older one if it exists