[WIP] Try to use java-module-packaging for jpackage

[koppor]

Refs https://github.com/JabRef/jabref-issue-melting-pot/issues/915

Tries to use https://github.com/gradlex-org/java-module-packaging

I "accidently" worked on JabSrv-CLI. Have no time now to port o JabKit, but I think, the issue is "universal".

Blocked by gradlex-org/java-module-packaging#57

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.