* Raise source level to Java 17 (except for model classes)
* Remove Nashorn script engine
* Upgrade spotless and add jvm options
See https://github.com/diffplug/spotless/issues/834
* Add suppression for findBugs false positive error
* Upgrade xtext to 2.29.0
* Adjust JNA
* Resolve itests
Signed-off-by: Jan N. Klug <github@klug.nrw>