[Micronaut] Add option to describe response wrappers

Created by: andriy-dmytruk

Based on this feature request: https://github.com/OpenAPITools/openapi-generator/issues/12059

Adds 2 options to describe in what to wrap the return types of operations:

• reactive=true will wrap the result in Mono
• wrapInHttpResponse=true will wrap the result in micronaut HttpResponse As an example the following method signatures can be produced:

Pet getPet(...args);
Mono<Pet> getPet(...args);
HttpResponse<Pet> getPet(...args);
Mono<HttpResponse> getPet(...args);

Also, based on PR https://github.com/OpenAPITools/openapi-generator/issues/12058 removes the parameter to reduce @Controller("${context-path}") to simply @Controller.

I ran the following to validate build:

./mvnw clean package
./bin/generate-samples.sh
./bin/utils/export_docs_generators.sh
./bin/meta-codegen.sh

./mvnw integration-test -P "java-micronaut-client,java-micronaut-server"

@wing328

feature request author: @pbthorste

Java technical committee: @bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608