feat: add to_list and to_pandas api's (#556)

Add `to_list` to return query results as list of python dict (so we're
not too pandas-centric). Closes #555

Add `to_pandas` API and add deprecation warning on `to_df`. Closes #545

Co-authored-by: Chang She <chang@lancedb.com>

python/tests/test_remote_client.py

@@ -86,7 +86,7 @@ async def test_e2e_with_mock_server():
                     columns=["id", "vector"],
                 ),
             )
-        ).to_df()
+        ).to_pandas()
 
         assert "vector" in df.columns
         assert "id" in df.columns