`to_df()` support

**Describe the feature**
glaredb already has a pip installer so it makes sense to have export capability of a query result to a dataframe.

**Desired UX**
N/A


```sql
df  = con.sql("SELECT _filename, * FROM 'gs://glaredb-bench/results/main/**/results-*.tsv';").to_df()
```
**Additional context**
N/A