We use Jandex as the language model all across Quarkus, and Gizmo is very often used in Quarkus. We should provide some level of integration, for example:

• create a class descriptor from Jandex DotName, Type and ClassInfo
• create a method/constructor descriptor from Jandex MethodInfo
• create a field descriptor from Jandex FieldInfo
• create an annotation from Jandex AnnotationInstance
• create a GenericType from Jandex Type (with type annotations)

My original plan was to do this in Gizmo 2 itself, but when I submitted a PR (quarkusio/gizmo#445), @dmlloyd disagreed with turning Gizmo 2 into a multi-module project and suggested to put the integration into Jandex. I don't have a problem with that, hence this issue.