The TOC of the 'Subsystem configuration' section of the Admin Guide should have an entry for every subsystem (ordered alphabetically, which is a separate topic.) So, we should have an independent section for each of the subsystems listed in https://docs.wildfly.org/31/Admin_Guide.html#Simple_configuration_subsystems.

These can all follow a basic pattern.

• Description of what the subsystem does.
• How to provision it via a layer (if possible)
• How to install it using CLI if not present (show commands to add extension and subsystem)