Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/form/classes/FormFactory.php

@@ -1,38 +0,0 @@
-<?php declare(strict_types=1);
-
-namespace Grav\Plugin\Form;
-
-use Grav\Common\Page\Interfaces\PageInterface;
-use Grav\Common\Page\Page;
-use Grav\Framework\Form\Interfaces\FormFactoryInterface;
-use Grav\Framework\Form\Interfaces\FormInterface;
-
-class FormFactory implements FormFactoryInterface
-{
-    /**
-     * Create form using the header of the page.
-     *
-     * @param Page $page
-     * @param string $name
-     * @param array $form
-     * @return Form|null
-     * @deprecated 1.6 Use FormFactory::createFormByPage() instead.
-     */
-    public function createPageForm(Page $page, string $name, array $form): ?FormInterface
-    {
-        return new Form($page, $name, $form);
-    }
-
-    /**
-     * Create form using the header of the page.
-     *
-     * @param PageInterface $page
-     * @param string $name
-     * @param array $form
-     * @return Form|null
-     */
-    public function createFormForPage(PageInterface $page, string $name, array $form): ?FormInterface
-    {
-        return new Form($page, $name, $form);
-    }
-}