[REQ] Support Polymorphic Annotations for JSONB

Is your feature request related to a problem? Please describe.

According to the official communication of EF, JSONB now supports polymorphism: https://projects.eclipse.org/projects/ee4j.jsonb/releases/3.0.0

There is not much documentation about it, but I found the following example:

@JsonbTypeInfo({      
  @JsonbSubtype(alias = "dog", type = Dog.class)     
  @JsonbSubtype(alias = "cat", type = Cat.class)})
interface Animal {} 

class Dog implements Animal {    
  public String isDog = true;
}
class Cat implements Animal {   
   public String isCat = true;
}

The behaviour seems quite similar to the existing @JsonTypeInfo Annotation of Jackson. We really need this feature in order to use polymorphic DTO's with JSONB. Alternatively we could use Jackson, but unfortunately the microprofile Generator does not support it (yet).

Describe the solution you'd like

As you already implemented a type info annotation for Jackson (see https://github.com/OpenAPITools/openapi-generator/blob/60dcf8613f6b75b606757c4a991fe018ad10ee99/modules/openapi-generator/src/main/resources/kotlin-spring/typeInfoAnnotation.mustache) it would be great to have the same for JSONB.

Start with modules/openapi-generator/src/main/resources/kotlin-spring/typeInfoAnnotation.mustache, which the issue cites, and trace how that template is selected for generated Java outputs. Identify the JSONB target generators and expected annotation behavior from the example; done means generated polymorphic DTOs use JSONB type-info annotations and relevant generation tests pass.