- Thymeleaf is now integrated and we can have a mix of angularjs and thy...

...meleaf pages.

- The 400.html and 500.html have been replaced by templates/error.html
- The error.html uses thymeleaf as templating. The language is automatically injected
- The locale is synchronized between the client and the server using the cookie.
   When the locale is changed in the angular application, the new locale is used by thymeleaf.
   If you passed the parameter named language with fr as value for example, the spring intercepts and the locale is changed on the server
   and the cookie is updated too. So the locale can be set on the frontend or on the backend.