[export_cpp] Export should only take a Scheduler as an input

Current export function take a GraphView AND a Scheduler.

This can be error prone if the Scheduler does not correspond to the GraphView.

Furthermore, the Scheduler contains the GraphView it is scheduling.

Thus I proposed to reduce the export API call to:

aidge_export_cpp.export(folder_name_to_generate, scheduler)

Do you agree @vtemplier ? :)