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 |

Das Issue nennt ConnectionManager.get_response() in dbt und die CommandComplete-Nachricht von PostgreSQL, enthält aber keine Dateien oder Tests aus dem Repository. Beginne damit, die Cursor-Implementierung und ihre Verarbeitung von Metadaten zu abgeschlossenen Befehlen zu lokalisieren, und vergleiche anschließend das Verhalten der verfügbaren Treiber mit den aufgeführten Attributen statusmessage und sqlstate. Als erledigt gilt die Aufgabe, wenn der Cursor SQL-Zustandsinformationen bereitstellt und die Details der betroffenen Operation für unterstützte Befehle erhalten bleiben.

Vom Indexierungsmodell aus dem Issue-Text verfasst.