[IMP] im_chat: added functionality to close focused chatView and set foc...

...us to next chatView on Esc keypress and added close button on chatList

- Task: https://www.odoo.com/web#view_type=kanban&model=project.task&action=333&active_id=1<field name="stage_id"/>31
- Pad: https://pad.odoo.com/p/r.xvGFnNn6ejnaaRoX