Want to make easier the lookup between a release, e.g DR20 and all the product versions associated with it. This includes pipeline versions, VAC versions, MOS target versions, etc. Consider whether this should live in the tree configs themselves or in a hosted file on the SAS. Could consider use of both, e.g. tree as default + patches in JSON.

This mapping exists in the datamodel product already, and could be migrated. Also provide a convenience function.