Consider deprecating old parsers API

**Feature request**
It would be great to have serialization for config.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_serialization` with default `false`.

Start by reconciling the title's old parsers API deprecation with the request for config serialization and the proposed enable_serialization option. Locate the configuration and parser entry points, then determine the intended serialized format, behavior when the option is false, and the tests needed to show the feature is complete.

Written by the indexing model from the issue text.