Feat: Refine and add more options to the CAYW endpoint

[palukku]

Follow up #13185 and #13187 (comment)

Closes palukku#5

Steps to test

You can test the simple-json format by using this command:
curl http://localhost:23119/better-bibtex/cayw?format=simple-json

for biblatex (which is the default format) you can use this and change the command (defaults to autocite)
curl http://localhost:23119/better-bibtex/cayw?format=biblatex&command=notautocite

Mandatory checks

• I own the copyright of the code submitted and I license it under the MIT license
• [/] Change in CHANGELOG.md described in a way that is understandable for the average user (if change is visible to the user)
• [/] Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• [/] Screenshots added in PR description (if change is visible to the user)
• [/] Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• [/] Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[trag-bot]

The field lacks proper nullability annotation (@nullable or @nonnull) which is required for public methods and fields to clearly indicate null handling behavior.

[trag-bot]

@trag-bot didn't find any issues in the code! ✅✨

[jabref-machine]

Your code currently does not meet JabRef's code guidelines. We use OpenRewrite to ensure "modern" Java coding practices. You can see which checks are failing by locating the box "Some checks were not successful" on the pull request page. To see the test output, locate "Tests / OpenRewrite (pull_request)" and click on it.

The issues found can be automatically fixed. Please execute the gradle task rewriteRun from the rewrite group of the Gradle Tool window in IntelliJ, then check the results, commit, and push.