Add a basic view for repository pull logs

Summary:
Depends on D18912. Ref T13046. Add a UI to browse the existing pull log table.

The actual log still has some significant flaws, but get the basics working.

Test Plan: {F5391909}

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13046

Differential Revision: https://secure.phabricator.com/D18914

src/applications/diffusion/controller/DiffusionPushLogListController.php

@@ -1,10 +1,7 @@
 <?php
 
-final class DiffusionPushLogListController extends DiffusionPushLogController {
-
-  public function shouldAllowPublic() {
-    return true;
-  }
+final class DiffusionPushLogListController
+  extends DiffusionLogController {
 
   public function handleRequest(AphrontRequest $request) {
     return id(new PhabricatorRepositoryPushLogSearchEngine())