Remove native CSS styles for JavaFX

Styles are configured for the following OS:

• MacOS (not supported by AF3 anymore)
• Windows 10 (not used at fortiss)
• Windows 8 (not supported by Microsoft anymore)
• Generic Windows support
  • It currently applied to Windows 11, where it lead to erroneous layout of the JavaFX Controls star rating widget (in #4389), which is worked around there with an empty CSS in ModelQualityFXViewPart.
  • in this ticket, the workaround should be removed.