The old system had some limitations :
- Not possible to chose a destination path different from the source path
- The copied kernel would be automatically included in the fwd file, sometime leading to unused includes

[Feat](Exports) Add a function to remove the optional inputs from the inputs list so they are not exported

[Feat](Exports) Add label export in generate_main_cpp() function and change the default inputs and labels destination folder from "ROOT" to "ROOT/data"