Updated JavaFX to version 19, Java to version 17.

[Oliver-Loeffler]

Could fix issue #21
Beside JavaFX/Java versions, I've bumped the version number to 3.2.0.

[Oliver-Loeffler]

Well, JavaFX 19 runs well with Java 11. Hence I've reverted the Java target version to 11.
Technically a JavaFX 19 based build is still something to be considered as with JLink and JPackage the exclusion of JavaFX 11 dependencies did not yield in a working executable. Need to continue to play around with this.

Also was thinking about versioning. Not sure of incrementing the minor version for that is the right approach. I've observed that for e.g. JDBC drivers the library version often gets a jdkXY or jreXY suffix. Same could help here, e.g. 3.1.0.javafx19 or 3.1.0.fx19. What do you think?