Switch to Zulip for chat-based communication

[jtpio]

Based on the discussions in jupyter/governance#182, there seems to be some traction to give Zulip a try for chat based communication within Jupyter.

The Jupyter Zulip is available here: https://jupyter.zulipchat.com. Which should also be available publicly without having to log-in.

For reference, there is also a draft PR to update the documentation and direct users to the Zulip instance: jupyterlab/jupyterlab#17031. Leaving it as a draft for now to leave space for discussion here if needed.

If you want to give it a try, and/or if you have any feedback, please don't hesitate to comment here or in jupyter/governance#182, thanks!

[jtpio]

cc @jupyterlab/jupyterlab-council for awareness

Maybe we don't need to have an explicit vote on this issue, if there is no objection to do the switch.