[dropdown] Add parent item type to allow submenus (#256)

Author: cavasinf

docs/components-dropdown.md

@@ -28,6 +28,13 @@ See Tabler documentation at https://preview.tabler.io/dropdowns.html
 | extraClass | Add custom class to the item                                                       |      `string`      | _empty string_ |
 |    attr    | Custom HTML attributes to add to the item                                          |      `Object`      |      `{}`      |
 
+##### Item type `parent`
+| Parameter | Description                                                                             |        Type        |  Default  |
+|:---------:|-----------------------------------------------------------------------------------------|:------------------:|:---------:|
+|   type    | `parent`                                                                                |      `string`      | `parent`  |
+| autoClose | See [autoClose option](https://getbootstrap.com/docs/5.2/components/dropdowns/#options) | `boolean / string` | `outside` |
+| children  | Array of the nested [items](#Item)                                                      |      `array`       |   `[]`    |
+
 ##### Item Options
 |    Parameter    | Description                      |   Type    |    Default     |
 |:---------------:|----------------------------------|:---------:|:--------------:|
@@ -132,6 +139,24 @@ See Tabler documentation at https://preview.tabler.io/dropdowns.html
     {
         type: 'divider',
     },
+    {
+        type: 'parent',
+        title: 'Parent',
+        children : [
+            {
+                title: 'Child 1',
+            },
+            {
+                title: 'Child 2',
+            },
+            {
+                title: 'Child 3',
+            },
+        ],
+    },
+    {
+        type: 'divider',
+    },
     {
         title: 'Logout',
         icon: 'back',

templates/components/dropdown.html.twig

@@ -50,6 +50,23 @@
                         {{ _html | raw }}
                     </div>
                 {% endif %}
+            {% elseif _type is same as 'parent' %}
+                {% set _children = item.children ?? [] %}
+                {% if item.autoClose is not defined %}
+                    {% set _autoClose = 'outside' %}
+                {% elseif item.autoClose is same as true %}
+                    {% set _autoClose = 'true' %}
+                {% elseif item.autoClose is same as false %}
+                    {% set _autoClose = 'false' %}
+                {% else %}
+                    {% set _autoClose = item.autoClose %}
+                {% endif %}
+                <div class="dropend">
+                    <a class="dropdown-item dropdown-toggle" data-bs-toggle="dropdown" data-bs-auto-close="{{ _autoClose }}" role="button">
+                        {{ _title }}
+                    </a>
+                    {{ _self.dropdown(_children) }}
+                </div>
             {% else %}
                 {% set classes = 'dropdown-item ' ~ (_disabled ? 'disabled ' : '') ~ (_active ? 'active ' : '') ~ _extraClass %}
                 {% if _type is same as 'link' %}