Bumped all Java versions to 17

[Sarenor]

Vermutlich etwas zu viel erwischt, aber so läuft der Test auf jeden Fall.

Du musst in die Run config noch --add-opens java.base/java.lang=ALL-UNNAMED als VM Option eintragen damits funktioniert.

[langfr]

There is separate development branch for Java 17 support.
master branch will go to Java 17 sooner or later, not yet decided.

P.S.:
you PR has a couple of conflicts. PR's should be based on current master branch.
To change from Java 11 to Java 17 it should be sufficient to change the property <maven.compiler.release>11</maven.compiler.release> in root pom.xml.

[Sarenor]

I know. That's why it's targeting the Development branch.

It's been done to quickly help Jochen with an issue he was having, you're free to decline this now that it should be resolved.

[jstaerk]

hatte ich dann auch noch gesehen mal schauen ob sicjhs trotzdem mergen lässt

[jstaerk]

lass uns mal lieber ${maven.compiler.release} nehmen und das auf 17 erhöhen