Instead of thread viewer having many dependencies, this allows models "having the thread viewer feature" to keep their own logic for themselves. The "create or update" part has to be done manually in this case (as opposed to using "insert") because thread viewer has no clear identifying data, since it would depend on which model is using it in the first place. closes odoo/odoo#70251 Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>