Add request/auth package to Nomulus release

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=147087621

java/google/registry/request/auth/AuthLevel.java

@@ -0,0 +1,52 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// 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.
+
+package google.registry.request.auth;
+
+/**
+ * Authentication level.
+ *
+ * <p>Used by {@link Auth} to specify what authentication is required, and by {@link AuthResult})
+ * to specify what authentication was found. These are a series of levels, from least to most
+ * authentication required. The lowest level of requirement, NONE, can be satisfied by any level
+ * of authentication, while the highest level, USER, can only be satisfied by the authentication of
+ * a specific user. The level returned may be higher than what was required, if more authentication
+ * turns out to be possible. For instance, if an authenticated user is found, USER will be returned
+ * even if no authentication was required.
+ */
+public enum AuthLevel {
+
+  /** No authentication was required/found. */
+  NONE,
+
+  /**
+   * Authentication required, but user not required.
+   *
+   * <p>In Auth: Authentication is required, but app-internal authentication (which isn't associated
+   * with a specific user) is permitted.
+   *
+   * <p>In AuthResult: App-internal authentication was successful.
+   */
+  APP,
+
+  /**
+   * Authentication required, user required.
+   *
+   * <p>In Auth: Authentication is required, and app-internal authentication is forbidden, meaning
+   * that a valid authentication result will contain specific user information.
+   *
+   * <p>In AuthResult: A valid user was authenticated.
+   */
+  USER
+}