Fixed issue 17120: After picking a new question theme, the settings are not properly updated (#1842)

Code reorganization.

• Added some comments.
• Have created helper functions as to be able to have a better outlook of what some function do.

Solution Summary.
The key of the solution is to be able to pickup theme attributes from a theme name and not from a the attribute set on the question. Then added a theme override parameter which will set which theme attributes should be picked up.

So now, question attributes may contain the attributes of a temp theme, which is not set on the DB.

• Move QuestionAttribute related static methods to a new service class

• Move QuestionAttribute related static methods to a new service class - Missing class

Co-authored-by: encuestabizdevgit <devgit@encuesta.biz>