MDL-70854 core: Add stored progress bars.

- Alters existing progress_bar class to support extension
    - Adds stored_progress_bar class as child of progress_bar
    - Adds webservice to poll stored progress
    - Updates database tables
    - Bumps version
    - Adds unit/behat tests

lib/classes/task/stored_progress_task_trait.php

@@ -0,0 +1,59 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace core\task;
+
+/**
+ * Trait to use in tasks to automatically add stored progress functionality.
+ *
+ * @package    core
+ * @copyright  2024 onwards Catalyst IT {@link http://www.catalyst-eu.net/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @author     Conn Warwicker <[email protected]>
+ */
+trait stored_progress_task_trait {
+
+    /** @var \core\output\stored_progress_bar|null $progress */
+    protected $progress = null;
+
+    /**
+     * Start a stored progress bar implementation for the task this trait is used in.
+     *
+     * @return void
+     */
+    protected function start_stored_progress(): void {
+        global $OUTPUT, $PAGE;
+
+        // To get around the issue in MDL-80770, we are manually setting the renderer to cli.
+        $OUTPUT = $PAGE->get_renderer('core', null, 'cli');
+
+        // Construct a unique name for the progress bar.
+        // For adhoc tasks, this will need the ID in it. For scheduled tasks just the class name.
+        if (method_exists($this, 'get_id')) {
+            $name = get_class($this) . '_' . $this->get_id();
+        } else {
+            $name = get_class($this);
+        }
+
+        $this->progress = new \core\output\stored_progress_bar(
+            \core\output\stored_progress_bar::convert_to_idnumber($name)
+        );
+
+        // Start the progress.
+        $this->progress->start();
+    }
+
+}