Update pandas parquet reader and writer (#429)

This commit exposes all the options that parquet read and write functionality for pandas expose,
fulfilling issue #406.

Note: extra_kwargs is to house extra key word arguments one can pass to the parquet reader and writer.
We don't expose those parameters because that's something on the user.

Squashed commits:

* feat(parquet): implemented and tested the writer for pandas parquet

* feat(parquet): implemented and tested the reader for pandas parquet

* feat(parquet): added to the pandas materializer example showing writing/reading of a dataframe

* feat(parquet): added to the my_script in pandas materializer example showing writing/reading of a dataframe

* feat(parquet): added an extra_kwargs dictionary to the PandasParquetWriter to handle kwargs not listed in Pandas' docs

* feat(parquet): added conditional dtype_backend support for PandasParquetReader class

* feat(parquet): updates unit test with assert_frame_equal usage

examples/pandas/materialization/my_script.py

@@ -90,6 +90,12 @@
         path="./df.feather",
         combine=df_builder,
     ),
+    to.parquet(
+        dependencies=output_columns,
+        id="df_to_parquet",
+        path="./df.parquet.gzip",
+        combine=df_builder,
+    ),
 ]
 # Visualize what is happening
 dr.visualize_materialization(
@@ -110,6 +116,7 @@
         "df_to_html_build_result",
         "df_to_stata_build_result",
         "df_to_feather_build_result",
+        "df_to_parquet_build_result",
     ],  # because combine is used, we can get that result here.
     inputs=initial_columns,
 )
@@ -121,5 +128,6 @@
 print(additional_outputs["df_to_html_build_result"])
 print(additional_outputs["df_to_stata_build_result"])
 print(additional_outputs["df_to_feather_build_result"])
+print(additional_outputs["df_to_parquet_build_result"])
 
 conn.close()