Automatically update all other instances when parent entity is published

When a parent entity is being published, all uses of those media items should be automatically updated to the latest revision of the media items.

This should do two things:

1. Update the "media_vid" value to point to the latest revision.
2. Identify every entity_type/entity_id which uses this media item and update it to point to the new revision.

This opens up a major issue:

• Revision history of nodes which have media attached will loose their correlation, so the revision history will become inaccurate.