Create a generic settings with the default case to be used for class and attributes settings

Problem/Motivation

In order to avoid duplicated settings should be create a new fieldgroup with general settings, and those settings can be used by classes and attributes as well

Steps to reproduce

Proposed resolution

Open the buildForm in the settings global page and create the new fieldgroup with type details and include this new general settings. Use the default case there. Include classes to class and attributes field and implement the JS validation in the front-end for both