Enforce common code style and formatting

[berezovskyi]

This will be easier in the long run

https://github.com/google/google-java-format is the only tool that I found that works both in Eclipse and IntelliJ.

Maven integration may make things easy via https://github.com/diffplug/spotless/tree/main/plugin-maven#google-java-format (+ can enforce/check other things). Alternatively, https://github.com/spotify/fmt-maven-plugin - also uses google-java-format under the hood.

Ideally add a CI check/fixer - https://github.com/axel-op/googlejavaformat-action should work in the --set-exit-if-changed mode for us, I guess.

[berezovskyi]

Starting small with OSLC/lyo-samples#171