Updates for python-pyarrow

• Add substrait module.
  • Fixes #1
• Harmonize PYARROW_WITH_PARQUET_ENCRYPTION with PARQUET_REQUIRE_ENCRYPTION in arrow.
• Update environment variables based on upstream documentation 1.
• Install pyarrow header files fixes.
  • Fixes #2 = Use a local install for testing.
• Switch back to cython from cython0 now that cython is supported 2.