community: Use IRC as community channel

Bug: https://git.ostc-eu.org/distro/docs/-/issues/86
Forwarded: https://booting.oniroproject.org/distro/docs/-/merge_requests/216
Relate-to: https://git.ostc-eu.org/distro/docs/-/merge_requests/211
Relate-to: https://booting.oniroproject.org/distro/docs/-/merge_requests/211


Thanks-to: Nawab Ahmad Reshi
Signed-off-by: Philippe Coval <philippe.coval@huawei.com>

community-chat-platform.rst

@@ -13,38 +13,23 @@ Community Chat Platform
 Overview
 ********
 
-The |main_project_name| project has a friendly community providing an open platform for
-discussions. `The |main_project_name| Mattermost instance <https://chat.booting.oniroproject.org>`_ is used
-as the primary communication tool by project members, contributors, and the
-community.
+The |main_project_name| project primarily uses a chatroom for community discussions, everyone is welcome!
+If you are looking for help or interested in contributing to the project, feel free to interact with maintainers, contributors and other community members.
 
-Authentication
-**************
+Project's chatroom is hosted in `Libera IRC Network <https://libera.chat/>`_. which is reachable using `IRC protocol <https://en.wikipedia.org/wiki/Internet_Relay_Chat>`_.
+IRC Channel #oniroproject can be joined using any IRC client by connecting to this address:
 
-To access the `|main_project_name| Mattermost instance <https://chat.booting.oniroproject.org>`_, one will
-need an account on the project's GitLab instance. The chat platform will handle
-the authentication through GitLab, redirecting the user accordingly. New
-account registration can be handled through this authentication process as well
-by using the ``Register now`` link in GitLab.
+- `<irc://libera.chat/#oniroproject>`_. 
 
-* Go to `<https://chat.booting.oniroproject.org>`
-* Login request will redirect you to `<https://booting.oniroproject.org>`
-   * Login using an existing account
-   * Create a new account following ``Register now`` link
-* The system will redirect you back to `<https://chat.booting.oniroproject.org>`
+Alternatively for user's convenience third party services can also be used from web (terms of service apply):
 
-Chat Channels
-*************
+- <https://web.libera.chat/#oniroproject>
+- <https://web.libera.chat/gamja/#oniroproject>
+- <https://kiwiirc.com/client/irc.libera.chat/#oniroproject>
 
-The `|main_project_name| Mattermost instance <https://chat.booting.oniroproject.org>`_ is organised in
-channels. The main one is the `Town Square <https://chat.booting.oniroproject.org/ostc/channels/town-square>`_
-and provides a default place for communication.
+The user might prefer to install an IRC client to connect to #oniroproject channel, like:
 
-To join/explore other a public channel, do the following:
+- `HexChat <http://hexchat.github.io/>`_ (Native IRC client for Linux, Windows)
 
-#. Select the **+** symbol at the top of the sidebar.
-#. Select **Browse Channels** and search through the list of Public channels.
-#. Select **Join** to join a specific communication channel.
-
-For more details on using our chat platform powered by Mattermost, check out the
-`Mattermost User’s Guide <https://docs.mattermost.com/guides/messaging.html>`_.
+  
+More details are explained on `the Libera website <https://libera.chat/guides/connect>`_.