I don't think that it was intentional, however the attempt to overtake was and that is what Rosberg has admitted to....if the former, he could expect up to a 3 race ban from FIA and, apparently, there are calls from them to Rosberg today.
However, it was bloody stupid to pull such a stunt on Lap 2 and has possibly cost Mercedes a one-two on the constructors. If I was Wolff and Lauda, I would be seething too. Not sure what Merc can do though, as any ban on Rosberg from within is just puncturing themselves in the tyre again, so to speak. Who is the back-up driver and what prospects does he (she) have if given the seat for one race....?