Use prettier-java.

Seems to be maintained. And better than two years ago (this PR is a follow-up to JabRef#10646)

• Automatic code update for maintainers (as a seperate step)
• Failing test for non-maintainers

Notes:

• More reading at Apply spring java format #716
• Needed to use "plain" call of prettier, because of [FEATURE] "Problem running prettier with" should output failure creyD/prettier_action#149 (we need a package.json nevertheless)

• Include git blame config: Use Prettier Java for automatic code formatting jabref#10646 (comment)

Note on 80 chars

It seems to be well-thought of

It is not the hard upper allowed line length limit. It is a way to say to Prettier roughly how long you’d like lines to be.

Source: https://prettier.io/docs/options

Steps to test

• Look at the diff
• Edit a file

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.