Uses [fmt-maven-plugin](https://github.com/spotify/fmt-maven-plugin) to
automatically (locally) apply [Google Java
Style](https://google.github.io/styleguide/javaguide.html) formatting
via the
[google-java-format](https://github.com/google/google-java-format)
plugin during `mvn compile` time.

During CI time, it checks for incorrect formatting on files *prior* to
compile to automatically reject failing commits so that reviewers have
fewer things to nit over and code style is more standardized.
- [x] Those file changes are initially omitted in order to validate this
part and make the PR easier to review. Will commit those once initial
review is done.

This is not *yet* enforced by a git pre-commit however, so developers
will have to add the changes that the `compile` stage applied after the
fact.

Additionally, it adds settings for
[VSCode](https://code.visualstudio.com/docs/java/java-linting#_applying-formatter-settings)
to apply these formattings during editing.
- [ ] Similar settings for Eclipse are currently missing.

Followup PR can also exclude this squashed PR from the `git blame`
analysis using a [`.git-blame-ignore-revs`
file](https://docs.github.com/en/repositories/working-with-files/using-files/viewing-a-file#ignore-commits-in-the-blame-view)

Closes #406