Delete --utxo-cost-per-word. No longer supporting this flag in any era going forward

[newhoggy]

Changelog

- description: |
    Delete `--utxo-cost-per-word`.  No longer supporting this flag in any era going forward
    This include deleting the CLI option from both legacy and era-base commands
# 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 protocol parameter was introduced in Alonzo era and then remove immediately thereafter.

There isn't a good reason to use this protocol parameter because we can hard fork to Babbage and use --utxo-cost-per-byte instead.

How to trust this PR

Highlight important bits of the PR that will make the review faster. If there are commands the reviewer can run to observe the new behavior, describe them.

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