Comments: Split out page comment reference logic to own component

Started support for editor view.
Moved comment elements to be added relative to content area instad of
specific target reference element.
Added relocating on screen size change.

resources/js/components/page-display.js

@@ -57,9 +57,6 @@ export class PageDisplay extends Component {
         }
     }
 
-    /**
-     * @public
-     */
     goToText(text) {
         const idElem = document.getElementById(text);