A few Typescript and Knex issues

Here are some misc things that I think could be changed. I've never written an open source PR before, I think it's easier if an existing contributor changed it:

1. Knex supports objects for joins and aggregates. It's especially useful for multi-column joins:

.join(
  'foo',
  {
    'foo.col1': 'bar.col1',
    'foo.col2': 'bar.col2',
  },
)

Something like this ((table: TableRef<QB>, columns: Record<string, ColumnRef>): QB;) could be added to JoinMethod.

2. Knex's limit now supports an additional param "skipBinding" (https://github.com/knex/knex/issues/4805). Objection's FirstOperation calls limit without skipBinding, which triggers an error in some databases (Materialize).

3. Objection's type exports UniqueViolationError, but this actually needs to be imported from db-errors.

4. Objection's Model type doesn't include "propertyNameToColumnName".

5. (not a real issue) addOperation and KnexOperation aren't documented or exposed through types, but they're useful for new or custom Knex operations.

Thanks for building and maintaining this awesome library!

Start by locating the type definitions for JoinMethod and Model, the FirstOperation implementation, and the exports for UniqueViolationError, addOperation, and KnexOperation. Compare each requested change with the referenced Knex behavior and existing Objection types, then verify that the affected exports and type signatures cover all five listed cases.