Client's public folder renamed to static

Regular campaign sender seems to have most of the code in place. (Not tested.)

client/static/mosaico/vendor/plugins/hr/plugin.js

@@ -0,0 +1,39 @@
+(function () {
+var hr = (function () {
+  'use strict';
+
+  var PluginManager = tinymce.util.Tools.resolve('tinymce.PluginManager');
+
+  var register = function (editor) {
+    editor.addCommand('InsertHorizontalRule', function () {
+      editor.execCommand('mceInsertContent', false, '<hr />');
+    });
+  };
+  var $_470wnubsjdud7abb = { register: register };
+
+  var register$1 = function (editor) {
+    editor.addButton('hr', {
+      icon: 'hr',
+      tooltip: 'Horizontal line',
+      cmd: 'InsertHorizontalRule'
+    });
+    editor.addMenuItem('hr', {
+      icon: 'hr',
+      text: 'Horizontal line',
+      cmd: 'InsertHorizontalRule',
+      context: 'insert'
+    });
+  };
+  var $_gb3ibbtjdud7abe = { register: register$1 };
+
+  PluginManager.add('hr', function (editor) {
+    $_470wnubsjdud7abb.register(editor);
+    $_gb3ibbtjdud7abe.register(editor);
+  });
+  function Plugin () {
+  }
+
+  return Plugin;
+
+}());
+})();