Fix Learn/FAQ page

[jlouvel]

Currently, this page contains the same content as the Download/FAQ page:
http://restlet.org/learn/faq

I'm pretty sure we had more interesting FAQ entries previously. We need to restore them. Found some entries in the user guide.

[jlouvel]

Move this page from user guide to the Learn/FAQ page:
http://restlet.org/learn/guide/2.2/appendices/faq

[jlouvel]

I've changed my mind, we will keep the FAQ inside the User Guide as it gives the ability to take into account versions.

Let's deleted the Learn/FAQ page altogether located here: http://restlet.org/learn/faq

[jlouvel]

Thanks