Implement Incremental Cardano DB in WASM client

[jpraynaud]

Why

The WASM client should be able to list and get details of Incremental Cardano DB snapshots.

What

Implement the Incremental Cardano DB signed entity type in the WASM Mithril client.

How

• Add the capability to handle CardanoDatabase in the fake aggregator
• Implement new commands in mithril-client-wasm as unstable:
  • list_cardano_database_v2
  • get_cardano_database_v2
• Add new verification step in client Manual multi-platform GitHub action