[Scala] added new scala-cask generator for the cask framework

[wing328]

based on #18046 with minor enhancements.

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/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH)
  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.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.1.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

[aaronp]

Thanks so much @wing328 !

what else do you need from me to merge?

[aaronp]

Thanks so much @wing328 - how can I buy you a beer/ thank you for your help?

Also, when does the next openapi docker image get built with this change?

[wing328]

published as part of the travis ci build: https://hub.docker.com/layers/openapitools/openapi-generator-cli/latest/images/sha256-bc770a2dd3ffe4c887534500b66b549840628e53ab2d0580af6dfeb6587a6e19?context=explore

how can I buy you a beer/ thank you for your help?

Just PM you via Slack :)