Drive Maniphest grouping and ordering through standard infrastructure

Summary: Ref T8441. Ref T7715. Ref T7909. Clean up all the ordering and grouping hacks in Maniphest so we can drive it through normal infrastructure, move it to SearchField, introduce Spaces, and eventually modernize the Conduit API.

Test Plan:
  - Executed all grouping/ordering queries, including custom queries.
  - Forced execution with old aliases; got modern results.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7909, T7715, T8441

Differential Revision: https://secure.phabricator.com/D13197

src/applications/project/controller/PhabricatorProjectBoardViewController.php

@@ -163,7 +163,7 @@ final class PhabricatorProjectBoardViewController
         PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
         PhabricatorQueryConstraint::OPERATOR_AND,
         array($project->getPHID()))
-      ->setOrderBy(ManiphestTaskQuery::ORDER_PRIORITY)
+      ->setOrder(ManiphestTaskQuery::ORDER_PRIORITY)
       ->setViewer($viewer)
       ->execute();
     $tasks = mpull($tasks, null, 'getPHID');