[Website] Add Zulip details to the Communication page

Zulip is currently used for real time development/technical discussions among many Arrow developers. We should add the channel and sign-in details to the page. Some guidance around the use of Zulip versus the mailing list would be helpful as well.

To sign in, go to [https://ursalabs.zulipchat.com](https://ursalabs.zulipchat.com/) and make an account.

**Reporter**: [Stephanie Hazlitt](https://issues.apache.org/jira/browse/ARROW-17663) / @stephhazlitt
#### Related issues:
- [[Website] Add Zulip details to the Communication page](https://github.com/apache/arrow/issues/32904) (duplicates)

_{**Note**: *This issue was originally created as [ARROW-17663](https://issues.apache.org/jira/browse/ARROW-17663). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Open the Apache Arrow community page linked in the issue and review its Communication section. Add the Zulip channel and sign-in details, plus guidance on when to use Zulip versus the mailing list; verify that the page clearly presents all requested information.

Written by the indexing model from the issue text.