Option to use entity's' field as subtitle

Problem/Motivation

Hi
It would be nice if Varbase Media Header can have an option to use an entity's field as subtitle instead having to work with template. it's may be useful for site editors.

Steps to reproduce

Proposed resolution

• On VMH settings page provide additional checkbox of : use subtitle
• After enabling the use subtitle warn the user to create a text filed with specific machine name may be field_vmh_subtitle
• if this field exist and is not hidden(if this make sens) display it under the VHM's title when viewing the entity