Add google-java-format formatter

[tschaffter]

We are currently using the Java formatter provided by the VS Code extension Language Support for Java(TM) by Red Hat. VS Code is configured to format Java files when saving using the configuration file eclipse-java-google-style.xml.

There are two issues with this approach:

• Google is moving away from eclipse-java-google-style.xml, which has not been updated in years (see this post).
• The files generated by the OpenAPI generator should be formatted similarly to the non-generated files. The only viable approach is to run the formatter programmatically, which is not possible using the extension Language Support for Java(TM) by Red Hat.

Tasks:

• Remove the file eclipse-java-google-style.xml from the workspace folder.
• Add google-java-format as an npm dependency.
• Configure VS Code to use google-java-format when saving Java files (see instructions).
• Document the formatter in docs/linters-and-formatters.md.

Future tasks:

• Check that Java files are properly formatted in Git hook and CI workflow

[tschaffter]

Added to Sprint 22.09