[C++][Parquet][Python] Deprecate engine version

The "engine version" setting has become a no-op, we should deprecate it and remove it in a later version.

**Reporter**: [Antoine Pitrou](https://issues.apache.org/jira/browse/ARROW-16710) / @pitrou

_{**Note**: *This issue was originally created as [ARROW-16710](https://issues.apache.org/jira/browse/ARROW-16710). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Begin with the migration documentation linked in the issue; it provides the stated context for the engine-version setting. The issue defines done as deprecating the no-op setting and removing it in a later version, but names no files or tests, so the implementation entry point and verification steps must first be identified.

Written by the indexing model from the issue text.