Organize callouts code under users

The following discussion from !68785 (merged) should be addressed:

• @mayra-cabrera started a discussion: (+7 comments)

  I agree the name is not perfect, and I can't think of a better option.

  But thinking about it a bit more, not sure if this one should be a concern, the point of a model concern is to make the code more re-usable by sharing it across different models, but this concern is very specific to User, we're using to reduce the logic of that model, at the moment I don't visualize any other model that could include this concern. I think the whole problem is that we're trying to centralize logic between Groups and Projects, which could be done by having a base class, something along the lines of:

  class BaseCallout
    has_many :callouts, class_name: 'UserCallout'
  
    # .... 
    def dismissed_callout_for_source?(feature_name:, ignore_dismissal_earlier_than: nil)
      callout = callouts_by_source_feature_name[source_feature_name]
  
      callout_dismissed?(callout, ignore_dismissal_earlier_than)
    end
  
    private
  
    def source_feature_name
      raise NotImplemented
    end
  
  end
  
  class ProjectCallout < BaseCallout
  
    private
  
    def source_feature_name
      ":project_#{project_id}_#{feature_name}"
    end
  end
  
  class GroupCallout < BaseCallout
  
    private 
  
    def source_feature_name
      ":group_#{group_id}_#{feature_name}"
    end
  end

  Thoughts?