We should use KDE's Breeze style for our Windows builds in the future.
Advantages:
- Kleopatra looks the same on all platforms.
 - The Breeze style is well supported for Windows because it's used for all Windows builds of apps published by KDE.
 - We don't have to chase bugs in Qt's Windows styles (like T7414).
 
Disadvantages:
- We have to build and package the Breeze style.