New module example: adding a section/widget to the order page

[Mark-H]

        $dispatcher->addListener(\Commerce::EVENT_DASHBOARD_PAGE_BEFORE_GENERATE, [$this, 'insertOnOrder']);

...

        $page = $event->getPage();
        if ($page->key === 'order') {
            $requests = new SimpleSection($this->commerce, [
                'title' => 'Payment Requests'
            ]);
            $requests->priority = 20; // position related to core sections 
            $requests->addWidget((new Grid($this->commerce))->setUp());

            $page->addSection($requests);
        }