Update to stylesheet.css from Java 11/17 + fix UI issues
The javadocs that I managed to add to a project with antora-javadoc had several small UI issues:
- some overlap between javadoc and UI
- some toolbar scrolling issues
- missing background colors of some javadoc elements
- wrong sizing of some of the orange "buttons"
I fixed these by updating stylesheet.css from java 11 (same as 17) and fixing the css on some places. I added comments to them, such that they can be recognized as intentional changes for the next time, when the css will be updated.
I also had to fix antora-ui-builder to fix the fonts packaging (antora-ui-builder!1).