docs(integrations): Document zoom video provider in /integrations.

Moves documentation about using zoom as video call provider
to /integrations. This documentation was earlier present
at /help/start-a-call and is moved as asked in issue #17588.

templates/zerver/integrations/zoom.md

@@ -0,0 +1,23 @@
+Zulip supports using Zoom as its video call provider.
+
+### Using Zoom
+
+1. Select Zoom as the organization's [video call provider](/help/start-a-call#changing-your-organizations-video-chat-provider).
+
+1. Zulip's [call button](/help/start-a-call) will now create meetings
+   using Zoom.
+
+The first time a user clicks the call button, they will be prompted to
+link their Zoom account with their Zulip account.
+
+**Note**: If you are self-hosting, you will need to [create a Zoom
+    application](https://zulip.readthedocs.io/en/latest/production/video-calls.html#zoom)
+    in order to use this integration.
+
+### Unlinking your Zoom account
+
+1. Log in to the [Zoom App Marketplace](https://marketplace.zoom.us/).
+
+1. Click **Manage** → **Installed Apps**.
+
+1. Click the **Uninstall** button next to the Zulip app.

zerver/lib/integrations.py

@@ -582,6 +582,14 @@ INTEGRATIONS: Dict[str, Integration] = {
         logo="images/integrations/logos/twitte_r.svg",
         doc="zerver/integrations/twitter.md",
     ),
+    "zoom": Integration(
+        "zoom",
+        "zoom",
+        ["communication"],
+        logo="images/integrations/logos/zoom.svg",
+        display_name="Zoom",
+        doc="zerver/integrations/zoom.md",
+    ),
 }
 
 BOT_INTEGRATIONS: List[BotIntegration] = [