Adding pages error fix

This feature is broken b/c when we added the saving of individual pages for moving blocks up and down.  We also try to save a new page that hasn't been added to the conference in the same way.  In the JPA layer we have the annotation in place to say that `PageEntity.conferenceId` is not updatable or insertable.  This upsets Postgres.

The solution is when updating a conference, first we check to see if there are any new pages.  If there are, we save them first by adding them to the conference and updating the conference.