Adds a new bounce exchange banner feature to the mass mailing website tools. This helps businesses capture visitor interest and grow mailing lists through a more prominent website signup prompt.

- Task: https://www.odoo.com/web/#id=9562&view_type=form&model=project.task
- Pad: https://pad.odoo.com/p/r.z6vfT0m2KIjzoY3f