Prepare: Enable gradle configuration cache

[koppor]

Follow-up to #13112

Prepres enabling of gradle's configuration cache.

• Replaces XJC plugin by https://github.com/bjornvester/xjc-gradle-plugin (which seems to be more maintained)
• Rewrites some custom gradle tasks to enable caching
• Final enablement blocked by Enable gradle configuration caching for prepareModulesDir beryx/badass-jlink-plugin#304

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I finally managed w/ ChatGPT and manual chain-of-thought to rewrite it. (Junie, Claude and ChatGPT could not help yesterday)

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.

[Siedlerchr]

• Task :jabgui:prepareMergedJarsDir of type org.beryx.jlink.PrepareMergedJarsDirTask: cannot serialize object of type 'org.gradle.api.internal.project.DefaultProject', a subtype of 'org.gradle.api.Project', as these are not supported with the configuration cache.

If I remmeber correctly there is somehow a way to disable it for a single task

[koppor]

Tweaks result in

Cannot retrieve Java toolchain: org.gradle.api.UnknownDomainObjectException: Extension of type 'JavaPluginExtension' does not exist. Currently registered extension types: [ExtraPropertiesExtension]

[trag-bot]

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