Move elements/ to ui/

appengine/swarming/ui/res/imp/common/pageable-data.html

 <!--
   This in an HTML Import-able file that contains the definition
   of the following elements:
 
     <pageable-data>
 
   The pageable-data element allows for easy paging of data from the swarming
   server. It displays a button to the user to go fetch more data, which will
   be appended to the output, rather than replaced, which is typical in
   elements like iron-ajax.
@@ skipping 151 matching lines @@
         }.bind(this));
       },
 
       _noMore: function(cursor) {
         return cursor === END;
       }
     });
   })();
   </script>
 </dom-module>