GDPR Data Erasure Plugin

In order to support GDPR requirements around purging personal information, a new (Job?) plugin should be written that can rewrite records to remove relevant information (Name, EmailAddress, etc). This might happen on a schedule (records that are "old", for some definition of old) or an action (eg: Expunge).

In order to avoid rekeying records and other issues with foreign keys, the approach will simply be to rewrite the relevant fields (eg: Pat Lee becomes GDPR Request #150). However, this will also rewriting Changelog records, and possibly some other (metadata?) fields where a person's name or other identifying information might be used in a non-structured way (such as actor_identifier).