💪 Persist and expose stored sentences

[beverage]

This will raise the question then whether or not we want to also persist the problems too.

• Confirm database schema and make updates where it may have diverged creating the feature.
• Break out random generation into a feature-based sentence generation.
• Allow sentence querying by features - combinations of pronoun types, correctness, negatedness, etc.
• Make that configurable from the command line.
• Expose a means of directly querying already generated sentences from the command line.
• Expose a means of directly querying already generated sentences from the command line by features listed above.

[beverage]

Sentence persistence: cbe517a

[beverage]

All but some of the sentence features complete: 6eb584b