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/app/pages/page/delete.js

@@ -1,15 +0,0 @@
-import $ from 'jquery';
-
-$(document).on('click', '[data-remodal-target="delete"]', function() {
-    let confirm = $('[data-remodal-id="delete"] [data-delete-action]');
-    let link = $(this).data('delete-url');
-
-    confirm.data('delete-action', link);
-});
-
-$(document).on('click', '[data-delete-action]', function() {
-    let remodal = $.remodal.lookup[$('[data-remodal-id="delete"]').data('remodal')];
-
-    global.location.href = $(this).data('delete-action');
-    remodal.close();
-});