support `Cursor` attribute to provide ANSI SQL State Code

While a `Cursor` attribute providing SQL State Code is not officially a part of [PEP 249: Python DB API 2.0 spec](https://peps.python.org/pep-0249/), there is an ANSI-standardized "SQL state code".

Many database drivers provide this as a `Cursor` attribute, dbt was able to depend on these drivers to provide it for `ConnectionManager.get_response()` method, which will report to users after successful queries the kind of operation performed (`SELECT`, `INSERT`, `CREATE`) and the numbers of rows affected. Originally the Redshift adapter for dbt, was supported by the `psycopg2` driver, which provides this information in `statusmessage`.

As reported in https://github.com/dbt-labs/dbt-redshift/issues/785, after migrating the driver dependency to `redshift-connector`, users are in a degraded state and receive less information than previously due to the SQL state not being available.

### Support for SQL state amongst popular analytics database drivers

| Driver | `Cursor` attribute (docs) |
|--------|--------|
| psycopg2 | [`statusmessage`](https://www.psycopg.org/docs/cursor.html#cursor.statusmessage) |
| `snowflake-connector-python` | [`sqlstate`](https://docs.snowflake.com/en/developer-guide/python-connector/python-connector-api#id7) |

### Ideal implementation

[Postgres's `CommandComplete` message](https://www.postgresql.org/docs/current/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-COMMANDCOMPLETE)

| Command | Tag | `rows` indicates the number of rows |
|------------------------|---------------------|-----------------------------------------------------------------------------|
| `INSERT` | `INSERT 0 rows` | inserted |
| `DELETE` | `DELETE rows` | deleted |
| `UPDATE` | `UPDATE rows` | updated |
| `MERGE` | `MERGE rows` | inserted, updated, or deleted |
| `SELECT` / `CREATE TABLE AS` | `SELECT rows` | retrieved |
| `MOVE` | `MOVE rows` | ursor's position has been changed by |
| `FETCH` | `FETCH rows` | that have been retrieved from the cursor |
| `COPY` | `COPY rows` | copied, only in `PostgreSQL` 8.2 and later |

El issue menciona ConnectionManager.get_response() en dbt y el mensaje CommandComplete de PostgreSQL, pero no incluye archivos ni pruebas del repositorio. Empieza localizando la implementación del cursor y cómo gestiona los metadatos de los comandos completados; después, compara el comportamiento de los drivers disponibles con los atributos statusmessage y sqlstate indicados. Se considera terminado cuando el cursor expone información del estado SQL y se conservan los detalles de la operación afectada para los comandos compatibles.

Escrito por el modelo de indexación a partir del texto del issue.