Simplify stake-address stake-delegation-certificate command across eras

[newhoggy]

Changelog

- description: |
    Simplify `stake-address stake-delegation-certificate` command across eras
# 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

Originally the command constructed a Delegatee and a Requirements.

Both of these were unnecessary because we can construct the certificate directly from the stake pool key hash and the stake credentials.

This more direct method has the advantage of not having to handle unsupported delegatees so there are fewer error cases to handle.

The simplification allows an error constructor to be deleted.

The caseShelleyToBabbageAndConwayEraOnwards function is temporarily defined here pending introduction into cardano-api. After moving that the new code is clearly much shorter.

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
• The changelog section in the PR is updated to describe the change
• Self-reviewed the diff

[newhoggy]

To be moved to cardano-api.