Add setStackable to ObjectItemList and use in Config

Summary:
This adds a new method for rendering the object list as a stackable set of items. Good for certain renderings like Config.

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Test Plan: Review list on iOS, Chrome, FF.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4637

src/applications/config/controller/PhabricatorConfigIssueListController.php

@@ -48,6 +48,7 @@ final class PhabricatorConfigIssueListController
   private function buildIssueList(array $issues) {
     assert_instances_of($issues, 'PhabricatorSetupIssue');
     $list = new PhabricatorObjectItemListView();
+    $list->setStackable();
 
     foreach ($issues as $issue) {
       $href = $this->getApplicationURI('/issue/'.$issue->getIssueKey().'/');