Move UserMigrationException to OCP and add @throws documentation

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

lib/public/UserMigration/IMigrator.php

@@ -38,6 +38,7 @@ interface IMigrator {
 	/**
 	 * Export user data
 	 *
+	 * @throws UserMigrationException
 	 * @since 24.0.0
 	 */
 	public function export(
@@ -49,6 +50,7 @@ interface IMigrator {
 	/**
 	 * Import user data
 	 *
+	 * @throws UserMigrationException
 	 * @since 24.0.0
 	 */
 	public function import(

lib/public/UserMigration/UserMigrationException.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2022 Côme Chilliet <come.chilliet@nextcloud.com>
+ *
+ * @author Côme Chilliet <come.chilliet@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCP\UserMigration;
+
+class UserMigrationException extends \Exception {
+}