split get_id_from_public_handle

Transfer some code from *get_id_from_public_handle* to *get_id_from_node_data*. *get_id_from_node_data* can now also be used to get the id for other types as well. In my case, get the id for newly created folders:

```folder = m.create_folder('new_folder')
node_id = m.get_id_from_node_data(folder)```