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/admin/themes/grav/templates/partials/dashboard-pages.html.twig

@@ -1,18 +0,0 @@
-{% if authorize(['admin.pages.list', 'admin.pages', 'admin.super']) %}
-    <div id="latest">
-        <div class="button-bar">
-            <a class="button" href="{{ admin_route('/pages') }}"><i class="fa fa-fw fa-file-text-o"></i>{{ "PLUGIN_ADMIN.MANAGE_PAGES"|t }}</a>
-        </div>
-        <h1>{{ "PLUGIN_ADMIN.LATEST_PAGE_UPDATES"|t }}</h1>
-        <table>
-        {% for latest in admin.latestPages if admin.latestPages %}
-            {% set route = latest.rawRoute %}
-            <tr>
-                <td class="triple page-title">
-                    <a href="{{ admin_route('/pages/' ~ route|trim('/')) }}"><i class="fa fa-fw fa-file-text-o"></i> {{ latest.title }}</a></td>
-                <td class="triple page-route">{{ route }}</td><td>{{ latest.modified|adminNicetime }}</td>
-            </tr>
-        {% endfor %}
-        </table>
-    </div>
-{% endif %}