Support array mode result type

Running this query in `duckdb-node`:

```sql
SELECT 1 as a, 2 as a;
```

returns:

```json
[{ "a": 2 }]
```

Ideally, it should captures all values by using arrays instead of objects:

```json
[[ 1, 2 ]]
```

In better-sqlite3, we can return arrays instead of objects by enabling the [.raw()](https://github.com/WiseLibs/better-sqlite3/blob/master/docs/api.md#rawtogglestate---this) method. I also see DBeaver can handle this correctly, which means that other client might has a support on this already.

The good news is calling `.columns()` with the example query would return two columns instead of one so hopefully adding "array mode" on the result can be easily implemented!

Thanks!