LedgerState.hs improvements

[jasagredo]

Changelog

- description: |
    In `Cardano.API.LedgerState`:
    - Use type aliases and patterns from ouroboros-consensus instead of re-defining them. 
    - Import entities from the right modules.
# 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...

How to trust this PR

These are just renamings for type aliases to reduce cognitive load. The exposed API remains the same.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[jasagredo]

This type has in fact changed, but it was mostly confirmed by @carbolymer that these functions are probably dead/unused.

[Jimbo4350]

LGTM!

[jasagredo]

I just re-signed the commits. Please @carbolymer or @Jimbo4350 set this PR to merge when ready