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/templates/forms/default/fields.html.twig

@@ -1,17 +0,0 @@
-{% set fields = prepare_form_fields(fields, name) %}
-{% set originalValue = null %}
-{% if fields|length %}
-  {% block outer_markup_field_open %}{% endblock %}
-  {% for field_name, field in fields %}
-    {% set value = form ? form.value(field.name) : data.value(field.name) %}
-    {% set field_templates = include_form_field(field.type, field_layout, fallback_field ?? 'text') %}
-    {% block inner_markup_field_open %}{% endblock %}
-    {% block field %}
-        {% include field_templates %}
-    {% endblock %}
-    {% block inner_markup_field_close %}{% endblock %}
-  {% endfor %}
-  {% block outer_markup_field_close %}{% endblock %}
-{% else %}
-  {% block empty_fields_markup %}{% endblock %}
-{% endif %}