docs(menu): add example of nested menus using dynamic data

#### Bug, feature request, or proposal:
Feature Request - Menu Docs

#### What is the expected behavior?
The docs would include an example of building a menu from a data structure similar to the [radio button docs](https://material.angular.io/components/radio/examples).

#### What is the current behavior?
The [menu docs](https://material.angular.io/components/menu/overview) only include a nested menu example using static HTML.

#### What are the steps to reproduce?
Working on a Stackblitz demo atm...

#### What is the use-case or motivation for changing an existing behavior?
This is a common use case for building application menus, especially for business applications. The data may come from a config file, a REST API, or some other source but it is very often not static and does not align with a static HTML example.

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
Angular 4.4.3
TypeScript 2.3.4
Chrome 61
OS X El Capitan

#### Is there anything else we should know?
Thank you for your hard work on this library!

Commencez par la documentation du menu et comparez son exemple statique de menu imbriqué avec le modèle de données dynamiques de la documentation des boutons radio. Examinez la démo StackBlitz signalée, si elle est disponible. Le travail est considéré comme terminé lorsque la documentation du menu inclut un exemple fonctionnel de menu imbriqué construit à partir d’une structure de données, avec un comportement clair d’après l’exemple.

Rédigé par le modèle d'indexation à partir du texte de l'issue.