Simplify the SimpleLinkService and use it to pass in a linkService instance in DefaultAnnotationsLayerFactory

Considering that most methods of `SimpleLinkService` are complete stubs, or practically "useless" considering what they return, we can actually simplify it even more.

*Note:* This depends on the previous patch, that did a small amount of refactoring of `PDFViewer_scrollPageIntoView`, since `PDFViewer.linkService.page` is no longer accessed.

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Currently the `pageviewer` components example doesn't work correctly (an error is printed in the console), since no `linkService` is present when the `AnnotationsLayerBuilder` is created.

*Note:* Given that this uses the `SimpleLinkService`, clicking on e.g. internal links won't actually do anything. However, given that internal links (and similar features) are pretty much useless when only *one* page is loaded the `pageviewer` example, I don't think that really matters.
Also, using the complete `PDFLinkService` would require a `PDFViewer` instance. That would significantly complicate the example, thus making it both less clear and less self contained.

web/annotations_layer_builder.js

@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/*globals PDFJS, CustomStyle, mozL10n */
+/*globals PDFJS, CustomStyle, mozL10n, SimpleLinkService */
 
 'use strict';
 
@@ -171,7 +171,8 @@ DefaultAnnotationsLayerFactory.prototype = {
   createAnnotationsLayerBuilder: function (pageDiv, pdfPage) {
     return new AnnotationsLayerBuilder({
       pageDiv: pageDiv,
-      pdfPage: pdfPage
+      pdfPage: pdfPage,
+      linkService: new SimpleLinkService(),
     });
   }
 };