Switch to a more recent java version (11 or 17 prefered)

[johanneshiry]

While we still use java 8 (official support ends 2022) the most recent LTS versions are 11 (official support ends in 2023) and 17 (official support ends in 2026). As sonarqube now requires java 11 to execute analyses and jGraphT also has switched to java 11 already preventing updates in PSDM, we should consider switch to at least java 11 or even better java 17 to be more stable for the next years.

Before we do this we should consider doing one final release in java 8.