Issue #3530958: Create an example code component for menus

For #3530958

• Adds an example component demonstrating a menu
• Adds a utility class for helping with json:api that sorts menus
• Extracts getPath from the Article List examples and adds it to the new utility class
• A little bit of naming tidy up to make things consistent

Testing Instructions

• Check out this branch
• Run npm run build and clear cache
• Run the following:

drush site:install minimal
drush recipe modules/contrib/experience_builder/tests/fixtures/recipes/base
drush pm:install experience_builder
drush php-eval "Drupal\experience_builder\Entity\Page::create(['title' => 'Homepage', 'type' => 'xb_page', 'path' => ['alias' => '/homepage', 'langcode' => 'en']])->save();"
composer require drupal/jsonapi_menu_items
drush pm:enable jsonapi jsonapi_menu_items menu_ui

• Login, go to /admin/config/services/linkset and enable the menu linkset endpoint
• Go to /admin/structure/menu/manage/main and create menu items, with nesting
• Go to /homepage and then click "Edit"
• Click + (Add) on the left hand menu, "+ Add new", give the component a name and click Add
• In the experience_builder module source code go to tests/fixtures/code_components/menus
• Copy the example into the editor and verify you get a menu rendered, with working submenu items
• Verify the data fetched from the menu endpoint is shown in the Data Fetch pane
• Save the code component, and drag it from the Components list to the content area of a page and verify the menu is rendered as expected