Make authentication optional

[Fabianopb]

When creating an application we include a User model with authentication using JWT and passport in the backend, and a simple session management in the frontend.

What if the user doesn't want to have authentication out of the box? So we should have opt-in authentication when bootstrapping the application, probably using a Node CLI question.

In the template the authentication related methods and files have to be modularized so this can be a maintainable solution.