I rewrote the the webapp creation view to satisfy new requirements. I
first changed the route to be coherent with the new routing system. I
changed the view name to be coherent with the new view naming (removing
the `View` as the end of the class name as it's obvious.

I rewrote completely the template for the webapp creation by adding two
panels, one for the basic and mandatory data and another one for the
advanced data.

I added a new button on the webapp list template that display a button
allowing only users in the `inria` group to create applications.

I created a template tag in order to be able to check if a user belongs
to a particular group in the template.

Signed-off-by: Matthieu Berjon <matthieu.berjon@inria.fr>