Add conway governance action view

[carlhammann]

Changelog

- description: |
    Add a command to view governance action files
# uncomment types applicable to the change:
  type:
  - feature        # introduces a new feature
  # - breaking       # the API has changed in a breaking way
  - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  - improvement    # QoL changes e.g. refactoring
  # - bugfix         # fixes a defect
  - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  # - documentation  # change in code docs, haddocks...

Context

This will close #8, which asks for a command to inspect governance action files. I've implemented with this interface:

Usage: cardano-cli conway governance action view --action-file FILE
                                                   [--output-format STRING]
                                                   [--out-file FILE]

  View a governance action.

Available options:
  --action-file FILE       Path to action file.
  --output-format STRING   Optional governance action view output format.
                           Accepted output formats are "json" and "yaml"
                           (default is "json").
  --out-file FILE          Optional output file. Default is to write to stdout.
  -h,--help                Show this help text

Every action file produced by any conway governance action * command should be understood as a possible --action-file. (I'm not testing all of them, only three...)

I've also slightly refactored the API of Cardano.CLI.Json.Friendly, because this was leading to a profusion of very similar functions.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• The change log section in the PR description has been filled in
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • round trip tests
  • integration tests
    See Running tests for more details
• 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-8.10.7 and ghc-9.2.7
• Self-reviewed the diff

[carlhammann]

@CarlosLopezDeLara I assume that we'd need similar commands for the other eras, and that they should somehow fit what is described in #313? For now, I decided to go with this minimal solution, as I don't know how these commands should fit into the overall interface.

[CarlosLopezDeLara]

decided

Not really, previous eras do not have governance actions.

This is exactly what we wanted! Nice one. Thank you!

[smelc]

LGTM 🍻