Core Platform Team/Initiative/MCR schema migration/Epics, User Stories, and Requirements


 * Ensure all direct or indirect access to pre-MCR fields is gated with the MCR migration stage.
 * Stop writing to pre-MCR fields in WMF production.
 * Make SCHEMA_COMPAT_NEW the default MCR migration schema
 * (after 1.34 release) Remove the ability to write pre-MCR fields, limit the ability to read pre-MCR fields to migration scripts. Remove the MCR migration stage config variable