status/report-2022-07-2022-09: Fix link to the Handbook

Fix link in cloud-init.adoc by:

• including shared/en/urls.adoc in _index.adoc;
• switching from extref to link.

Reviewed by: carlavilla
Approved by: debdrup (status blanket)
Differential Revision: https://reviews.freebsd.org/D37033