[core][general] added opportunity to configure names of metadata files

[poisonedvk]

fixes #10403

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.
• Run the following to build the project and update samples:

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

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
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[wing328]

cc @OpenAPITools/generator-core-team as the change covers the default codegen/generator

[wing328]

Thanks for the PR. I'm ok with the enhancement.

[poisonedvk]

Thanks for the PR. I'm ok with the enhancement.

Thank you for merging it!