PARQUET-1428: Move columnar encryption into its feature branch
PARQUET-1428: Move columnar encryption into its feature branch

Revert "PARQUET-1401: optional RowGroup fields for handling hidden columns (#104)"

This reverts commit 677ed8ea23c60e5e42a4c537a454544884525593.

apache/parquet-format,apache/parquet-format,apache/parquet-format