This commit is a significant rewriting of client-side discuss, chatter,
chat window, and messaging menu using OWL. The behavior should be broadly
the same, with some slight functional changes here and there.

From a technical standpoint, the code of messaging is mainly organized in 2
main groups of modules:

- models, which are logical entities that depict the client-side state of
  messaging as a whole.
- components, which are in charge of displaying information from models.

This refactoring also introduces new JS guidelines regarding folder structure
(/static) and naming rules for JS modules.

Community PR: https://github.com/odoo/odoo/pull/39023
Enterprise PR: https://github.com/odoo/enterprise/pull/6249

Task-1914207

This PR is a collaborative work by Alexandre, Julien, Sébastien and Xavier,
with the precious help of Lucas to speed it up towards the end.

closes odoo/odoo#39023

Related: odoo/enterprise#6249
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>
Co-authored-by: Alexandre Kühn <aku@odoo.com>
Co-authored-by: Julien Giannone <jgi@odoo.com>
Co-authored-by: Lucas Perais <lpe@odoo.com>
Co-authored-by: Sébastien Theys <seb@odoo.com>
Co-authored-by: Xavier Dubuc <xdu@odoo.com>

closes odoo/odoo#52826

Related: odoo/enterprise#11084
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

The purpose is to have more common code for failure and notifications, with less
override in `sms` and `snailmail`.

task-2176017

closes odoo/odoo#44170

Related: odoo/enterprise#9140
Related: odoo/upgrade#918
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

This commit prevents sending a notification within Odoo when a
message is posted from a mailing channel to a user whose notification
management preference is set to "Handle by Emails".

Task-ID 2033302

closes odoo/odoo#36000

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

Currently when you open, for example, 5 chat windows on the desktop,
each of those windows will be opened on mobile as well.
The big issue with that is that I have to shut down all windows before
starting to work on the application.

To make things simple, you have to explicitly open chat window to
make it appears on mobile. Synchronization is blocked in both direction.
We don't update the chat window state on the server and we no longer
consider notifications (bus) about it.

Tests were added in enterprise.

Task ID: 1891952

closes odoo/odoo#41052

Related: odoo/enterprise#6943
Signed-off-by: Adrien Dieudonné (adr) <adr@odoo.com>

This commit allows a livechat operator to send a chat request to a
connected and available website_visitor.

A visitor is considered as connected if his last tracked website.page request
was within the last 5 minutes.
A visitor is available if he doesn't have an active livechat conversation
(mail_channel with type = livechat).
  - If another operator sent him a chat request
  - Or if the visitor asked himself to speak with an operator
    (via the normal and existing flow)

A livechat conversation is active while the visitor haven't left the conversation.
An operator cannot leave a livechat conversation, only the visitor can.

The flow to send a chat request:
  - On the visitor view (tree or form), operator click on 'send chat request'
    (button or livechat icon)
  - A empty conversation with the visitor pops up at operator side.
  - While the operator didn't send a message, the visitor won't see the conversation.
  - The operator can type a message to the user
  - If the operator close the chat without sending any messages,
    the chat request AND the mail_channel are both deleted.
    In this case, the visitor is then available to send him a new chat request.
  - If the operator send a message, at the visitor's next action
    (page navigation on pages that allows livechat, based on livechat rules),
    the conversation will pop up at visitor side, using the livechat button widget.
    The visitor won't be able to request a livechat conversation with an operator until
    he leaves the chat requested by the operator.
  - Once the visitor leaves (with or without rating) the conversation :
        - the operator is notified that the visitor has left the conversation
        - the chat request is deleted to keep the chat request table clean and minimal
        - the livechat conversation if set to inactive.
  - The visitor is now available again to send him a chat request.

This feature uses the already existing livechat_session cookie mechanism,
so no further code modification was needed to make this work.
It's directly integrated is existing livechat flow.

The chat_request model is only useful to quickly check if a visitor has a chat request
and to send the livechat conversation info to the visitor via the livechat_session cookie.

This commit also add a website_visitor banner info on discuss view :

To be able to quickly see all the relevant information of a website visitor
while talking with in discuss view, a fixed banner have been added.
Only the discuss view will benefit from this because detached chatter window
is to small to display such banner.

Task ID: 34624
PR #2028059

This commit adds a new mailbox in the Discuss app called 'History'.
Messages that have been marked as read are moved to 'History'.

Notifications are required to link history messages to users. So
notifications are now deleted after they are more tha 6 months old.
This means History mailbox keeps less than 6 months old messages.

Note that this feature only works when user notifications are handled
in Odoo. This can be set in the user preferences, under the
"Notification Management" section.

Task-ID 402597