Move files in Phabricator one level up

Summary:
- `kill_init.php` said "Moving 1000 files" - I hope that this is not some limit in `FileFinder`.
- [src/infrastructure/celerity] `git mv utils.php map.php; git mv api/utils.php api.php`
- Comment `phutil_libraries` in `.arcconfig` and run `arc liberate`.

NOTE: `arc diff` timed out so I'm pushing it without review.

Test Plan:
/D1234
Browsed around, especially in `applications/repository/worker/commitchangeparser` and `applications/` in general.

Auditors: epriestley

Maniphest Tasks: T1103

src/applications/files/engine/PhabricatorS3FileStorageEngine.php

@@ -0,0 +1,130 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Amazon S3 file storage engine. This engine scales well but is relatively
+ * high-latency since data has to be pulled off S3.
+ *
+ * @task impl       Implementation
+ * @task internal   Internals
+ * @group filestorage
+ */
+final class PhabricatorS3FileStorageEngine
+  extends PhabricatorFileStorageEngine {
+
+/* -(  Implementation  )----------------------------------------------------- */
+
+
+  /**
+   * This engine identifies as "amazon-s3".
+   *
+   * @task impl
+   */
+  public function getEngineIdentifier() {
+    return 'amazon-s3';
+  }
+
+
+  /**
+   * Write file data into S3.
+   * @task impl
+   */
+  public function writeFile($data, array $params) {
+    $s3 = $this->newS3API();
+
+    $name = 'phabricator/'.Filesystem::readRandomCharacters(20);
+
+    AphrontWriteGuard::willWrite();
+    $s3->putObject(
+      $data,
+      $this->getBucketName(),
+      $name,
+      $acl = 'private');
+
+    return $name;
+  }
+
+
+  /**
+   * Load a stored blob from S3.
+   * @task impl
+   */
+  public function readFile($handle) {
+    $result = $this->newS3API()->getObject(
+      $this->getBucketName(),
+      $handle);
+    return $result->body;
+  }
+
+
+  /**
+   * Delete a blob from S3.
+   * @task impl
+   */
+  public function deleteFile($handle) {
+
+    AphrontWriteGuard::willWrite();
+    $this->newS3API()->deleteObject(
+      $this->getBucketName(),
+      $handle);
+  }
+
+
+/* -(  Internals  )---------------------------------------------------------- */
+
+
+  /**
+   * Retrieve the S3 bucket name.
+   *
+   * @task internal
+   */
+  private function getBucketName() {
+    $bucket = PhabricatorEnv::getEnvConfig('storage.s3.bucket');
+    if (!$bucket) {
+      throw new PhabricatorFileStorageConfigurationException(
+        "No 'storage.s3.bucket' specified!");
+    }
+    return $bucket;
+  }
+
+  /**
+   * Create a new S3 API object.
+   *
+   * @task internal
+   * @phutil-external-symbol class S3
+   */
+  private function newS3API() {
+    $libroot = dirname(phutil_get_library_root('phabricator'));
+    require_once $libroot.'/externals/s3/S3.php';
+
+    $access_key = PhabricatorEnv::getEnvConfig('amazon-s3.access-key');
+    $secret_key = PhabricatorEnv::getEnvConfig('amazon-s3.secret-key');
+
+    if (!$access_key || !$secret_key) {
+      throw new PhabricatorFileStorageConfigurationException(
+        "Specify 'amazon-s3.access-key' and 'amazon-s3.secret-key'!");
+    }
+
+    $s3 = new S3($access_key, $secret_key, $use_ssl = true);
+
+    $s3->setExceptions(true);
+
+    return $s3;
+  }
+
+}