Feat: Implement a basic Zotero picker compatible CAYW endpoint

[palukku]

Adds the ability to use the extensions which normally can be used with better-bibtex to startup the cayw citation picker in zotero.

Closes #13187

The cayw endpoint and gui can be opened with

curl http://localhost:23119/better-bibtex/cayw

after that it opens up a window where you can search

Provide path to bif file - and say JSON format

curl http://localhost:23119/better-bibtex/cayw?librarypath=C%3A%5CUsers%5CDEMO%5CDownloads%5CChocolate.bib&format=json

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.

[subhramit]

Great progress so far, Philip!
I have left some comments.

Also, if possible, please add javadoc to every non-trivial method you write during the project (by non-trivial I mean ones which are not getX, setZ or displayP etc.) so that any maintainer taking a walk can review your code easily without having to gather context.
^This suggestion holds for all GSoC students @Yubo-Cao @Kaan0029 @wanling0000.

[koppor]

Tmp moved to JabRef#709

[trag-bot]

Method can return null but doesn't use Optional to explicitly handle the null case, violating the principle of not returning null from public methods.

[trag-bot]

GUI code is directly implemented in the resource class instead of being delegated to a proper logic layer in org.jabref.logic package.

[trag-bot]

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

[trag-bot]

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

[jabref-machine]

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You can then run these tests in IntelliJ to reproduce the failing tests locally. We offer a quick test running howto in the section Final build system checks in our setup guide.