[ADD] XML export

Allow users to export data in a re-importable XML file

- Task: https://www.odoo.com/web/#id=8803&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.GQ9qOYpLqUjA9L7D
in order to create separate record for one2many we will need to pass 'id' in that dict so i have updated dict and created temporary dict to pass Id as field in that data.