[ticket/13654] Moving reporting into controller

Moving report.php's content into different services and controllers to
better comply with the MVC model.

Also implementing:
 * Replacement for reasons_display()
 * Adding assign_meta_refresh_var() to \controller\helper
 * Adding separate routes for easy configuration
 * Updating unit tests to expect to correct results
 * Add BC tests

PHPBB3-13654

phpBB/phpbb/report/report_handler_interface.php

@@ -0,0 +1,43 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\report;
+
+interface report_handler_interface
+{
+	/**
+	 * Reports a message
+	 *
+	 * @param int		$id
+	 * @param int		$reason_id
+	 * @param string	$report_text
+	 * @param int		$user_notify
+	 * @return null
+	 * @throws \phpbb\report\exception\empty_report_exception		when the given report is empty
+	 * @throws \phpbb\report\exception\already_reported_exception	when the entity is already reported
+	 * @throws \phpbb\report\exception\entity_not_found_exception	when the entity does not exist or the user does not have viewing permissions for it
+	 * @throws \phpbb\report\exception\invalid_report_exception		when the entity cannot be reported for some other reason
+	 */
+	public function add_report($id, $reason_id, $report_text, $user_notify);
+
+	/**
+	 * Checks if the message is reportable
+	 *
+	 * @param int	$id
+	 * @return null
+	 * @throws \phpbb\report\exception\already_reported_exception	when the entity is already reported
+	 * @throws \phpbb\report\exception\entity_not_found_exception	when the entity does not exist or the user does not have viewing permissions for it
+	 * @throws \phpbb\report\exception\invalid_report_exception		when the entity cannot be reported for some other reason
+	 */
+	public function validate_report_request($id);
+}