Co-authored-by: Christophe HAMERLING <chamerling@linagora.com>
Co-authored-by: Klemens Arro <klemens.arro@admcloudtech.com>
Co-authored-by: Goran Urukalo <goran.urukalo@teletrader.com>

The configured server URL will be used when the room URL is not
a full URL. If a full URL is given, the target server is joined.

The default server URL is https://meet.jit.si

Use the concept of a "server URL", since it's URLs we are dealing with,
not actul domains.