We replace knight command with change_user_role command which
allows us to change role of a user to owner, admins, member and
guest. We can also give/revoke api_super_user permission using
this command.
Tweaked by tabbott to improve the logging output and update documentation.
Fixes#16586.
We're migrating to using the cleaner zulip.com domain, which involves
changing all of our links from ReadTheDocs and other places to point
to the cleaner URL.
* Moves "Management commands" to a top-level section.
* Moves "Scalability" as a subsection at the bottom of "Requirements".
* Moves "Monitoring" as a subsections at the bottom of "Troubleshooting".
* Replaces "API and your Zulip URL" with a link to REST API docs. This
documentation text has been irrelevant for some time.
* Removes maintain-secure-upgrade from the TOC but the file remains to
avoid breaking old links from release blog posts and emails.