Remove sqlalchemy type ignores in the backend.

[czaloom]

Problem Description

The Query object is a major source of type ignores in the backend.

Feature Description

Condense the Query generator object into two strongly typed functions:

• generate_select
• generate_query

Additional Context

Before

q = Query(
    models.Label.key,
    models.Label.value,
    models.Prediction.score,
).predictions(as_subquery=False)
q = q.where(models.Prediction.annotation_id == annotation.id)  # type: ignore - SQLAlchemy type issue
labels = [
    schemas.Label(
        key=scored_label[0],
        value=scored_label[1],
        score=scored_label[2],
    )
    for scored_label in db.query(q.subquery()).all()
]

After

query = (
    generate_query(            
        models.Label.key,
        models.Label.value,
        models.Prediction.score,
        db=db,
        label_source=models.Predication,
    )
    .where(models.Prediction.annotation_id == annotation.id)
)
labels = [
    schemas.Label(
        key=scored_label[0],
        value=scored_label[1],
        score=scored_label[2],
    )
    for scored_label in query.all()
]