Adding Api per operation option to JaxRS and Spring server generators.

Created by: pablobastidasv

Added the option apiPerOperation which work similar to useTags but instead of generate a Java class per each annotation, this will tells to Spring and JaxRS server generators to create a Class per each operation (url + method).

2 new unit tests were added, one per each generator.

fix #9219

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
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  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh

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