Remove optparse-applicative-fork dependency, and functions depending on it

[smelc]

Changelog

- description: |
    Removes the dependency to `optparse-applicative-fork`, as it is unused internally and not useful for users.
# 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
  - refactoring    # QoL changes
  # - 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

API depends on optparse-applicative-fork here. This dependency is not really useful and in addition it's a fork we depend on, not on the main version.

How to trust this PR

1. Code compiles.
2. CLI PR adapting to this change exists: Move parsing helpers from API cardano-cli#894

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• Self-reviewed the diff

[carbolymer]

LGTM. Thanks! Can you mark this PR as breaking as well? We're changing the exposed API.