Read only Questions API.

I made this mainly so @iankronquist could play with SUMO data via an API that works like the input APIs.

I hacked this together in an hour or so, so it might be really goofy.

f?
tl;dr, this does nothing, so I should probably remove it.

This is mainly cargo culting the default implementation of this method. The default implementation of `check_object_permission` for `generics.RetrieveAPIView` is to check all the permission on the class, which by default is empty. Since this class doesn't define any permissions, it is basically a no-op that isn't needed.