Cleaning the framework and adding basic authentication

- I have removed the Acme namespace and all its bundles
- I have removed the Acme references in the routes and in the AppKernel
- I have created 2 namespaces : Briceaiello and Supinfochina
- New bundle "Home" in Supinfochina for the public home page
- New bundle "User" in Briceaiello for the users management
- I have configured a basic users provider for testing
- I have added twitter bootstrap for basic css purpose