[IMP] mail: chatter: remove insert_message method, instead of push ea...

...ch message to DOM using insert_message, create render_thread that will render each of it's message

- Task: https://www.odoo.com/web#id=8546&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.AdsUG2IZU0s39ry8
Unuseful diff