[palas]

Description

This PR adds a status command for cardano-testnet tool, that checks the status of a testnet generated by cardano-testnet. It takes a testnet configuration dir path, and an optional --json flag that makes the output format be JSON following the schema also defined in this PR.

If the --json format is not specified, the output format is human readable, and includes an ASCII table that shows the information about each of the nodes in the testnet.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
  • integration tests
    See Running tests for more details
• Any changes are noted in the CHANGELOG.md for affected package
  • cardano-node-chairman, cardano-submit-api and cardano-testnet instead need a
    changelog fragment in <package>/.changes/, because their CHANGELOG.md is generated
    from fragments at release time. Copy _TEMPLATE.yml from that directory, or run
    nix run github:input-output-hk/cardano-dev#herald -- new
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-9.6 and ghc-9.12
• Self-reviewed the diff

[carbolymer]

Exception handling needs improving.

We could improve error handling code by not using ExceptT.

[Jimbo4350]

LGTM