Upgrade Project to Java 17

Afterr the involuntary downgrade to JDK11, I really want to get this project up to date to JDK17. Main Problem: SL4J compatibility. 

* [ ] Figure out what exactly causes the SL4J compilation errors when using a JDK >11
* [ ] Fix it (submit PR to SL4J if successful)
* [ ] Upgrade JSR Project to JDK17
* [ ] Use new language features (String templates!!, pattern matching, etc) 