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/email/vendor/symfony/messenger/README.md

@@ -1,29 +0,0 @@
-Messenger Component
-===================
-
-The Messenger component helps applications send and receive messages to/from
-other applications or via message queues.
-
-Sponsor
--------
-
-The Messenger component for Symfony 5.4/6.0 is [backed][1] by [SensioLabs][2].
-
-As the creator of Symfony, SensioLabs supports companies using Symfony, with an
-offering encompassing consultancy, expertise, services, training, and technical
-assistance to ensure the success of web application development projects.
-
-Help Symfony by [sponsoring][3] its development!
-
-Resources
----------
-
- * [Documentation](https://symfony.com/doc/current/components/messenger.html)
- * [Contributing](https://symfony.com/doc/current/contributing/index.html)
- * [Report issues](https://github.com/symfony/symfony/issues) and
-   [send Pull Requests](https://github.com/symfony/symfony/pulls)
-   in the [main Symfony repository](https://github.com/symfony/symfony)
-
-[1]: https://symfony.com/backers
-[2]: https://sensiolabs.com
-[3]: https://symfony.com/sponsor