Entity "Reference type" - Add ability to override labels and visibility of Reference fields

Problem/Motivation

Entity type "Reference" have a static number of fields defined in the code.
Site administrator should have an ability to change these fields based on a reference type (publication type).

Proposed resolution

Add new fields to "Reference type" configuration schema.
Based on this configuration edit form of the Reference entity will be overridden.

User interface changes

Edit form of the Reference entity type will contain a less amount of fields with overridden labels.