parquet reader implementation as a new input type

[gaudyb]

Description

I extended the input type inside GraphRAG to be able to use parquet files.

Proposed Changes

• New parquet reader implementation as a new input type.

Checklist

• I have tested these changes locally.
• I have reviewed the code changes.
• I have updated the documentation (if necessary).
• I have added appropriate unit tests (if applicable).