There's documentation on how to configure two-way SSL here:
The documentation describes how to configure and make use of an Elytron trust-manager that makes use of your trust store.
How can I configure this in the standalone.xml, like we had in version 10?
When you run those management commands, the sucessful execution of those will update the standalone (or domain) configuration file, which is in use when you started the WildFly server. You can then use the content of that configuration file as a reference.