Add bin/worker flood, for flooding the task queue with work

Summary: Ref T6615. Ref T3554. We need better tooling around the queue eventually, so start here.

Test Plan: Added 100K+ tasks locally with `bin/worker flood`. Executed some of them with `bin/phd debug taskmaster` (we already have a TestWorker, used in unit tests).

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T3554, T6615

Differential Revision: https://secure.phabricator.com/D10894

scripts/setup/manage_worker.php

@@ -0,0 +1,21 @@
+#!/usr/bin/env php
+<?php
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+
+$args = new PhutilArgumentParser($argv);
+$args->setTagline('manage task queue');
+$args->setSynopsis(<<<EOSYNOPSIS
+**worker** __command__ [__options__]
+    Manage the task queue.
+
+EOSYNOPSIS
+  );
+$args->parseStandardArguments();
+
+$workflows = id(new PhutilSymbolLoader())
+  ->setAncestorClass('PhabricatorWorkerManagementWorkflow')
+  ->loadObjects();
+$workflows[] = new PhutilHelpArgumentWorkflow();
+$args->parseWorkflows($workflows);