Incorporate global behavior to highlight hovered-over items.

[salvamomo]

This started as something for scaling background in bspweb. It simply adds a class to a given DOM element whenever any of its child items is on hover. This is useful because sometimes you want to apply css effects on the parent item when it's hovered, but passing over child items might make it lose the ":hover" meta state.

      var mirageViewsRowClass = '.mirage-views-row-hover .views-row';

      $(mirageViewsRowClass).bind('mouseenter', function(e) {
        $(e.target).closest('.views-row').addClass('row-hovered');
      });

      $(mirageViewsRowClass).bind('mouseleave', function(e) {
        $(e.target).closest('.views-row').removeClass('row-hovered');
      });```

Then had to implement something similar (equal except for the class names) for 
paragraphs, duplicating code. It's something rather trivial but will be probably common. 
Having a class makes it easier to target states within CSS, and also to keep it in line 
with BEM naming conventions.

Use this ticket to incorporate this logic, but also to start a simple but 
dev-friendly way to see usage, what JS utilities we have, etc.