Modernize Audit search engine

Summary:
Fixes T9279. Modernizes the SearchEngine and Query classes. User-facing changes:

  - Added order by commit date, default to order by commit date with newest commits first.
  - Added explicit "Needs Audit by".
  - Added new `packages(...)` typeahead function.
  - Picked up automatic subscribers, projects, and order fields.

This changes behavior a little bit: we previously attempted to exclude, e.g., commits which a package you own needs to audit, but which you have resigned from. This is difficult in general and I think it needs a more comprehensive solution. This shouldn't impact users much, anyway.

Test Plan: {F767628}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9279

Differential Revision: https://secure.phabricator.com/D14013

src/applications/home/controller/PhabricatorHomeMainController.php

@@ -349,9 +349,8 @@ final class PhabricatorHomeMainController extends PhabricatorHomeController {
 
     $query = id(new DiffusionCommitQuery())
       ->setViewer($user)
-      ->withAuditorPHIDs($phids)
+      ->withNeedsAuditByPHIDs($phids)
       ->withAuditStatus(DiffusionCommitQuery::AUDIT_STATUS_OPEN)
-      ->withAuditAwaitingUser($user)
       ->needAuditRequests(true)
       ->needCommitData(true)
       ->setLimit(10);