🍒windows: force sane style, color, icons

there's various weird issues to do with the defaults in frameworks not kicking in reliably and debugging this is a bit of a nightmare. instead force suitable values

this notably fixes:

• radio buttons, check boxes and sliders being incorrectly scaled, by using the breeze style
• the icons not coloring correctly, by forcing breeze icon theme
• the colors not adapting correctly to system theme changes, by ensuring we have a kcolorschememanager

BUG: 487104 (cherry picked from commit 29e76d16)