qt: CSD icons on windows should use Segoe font

On windows, the minimize/maximize/close buttons are drawn as CSD (client side decoration) by default, this means that we draw the buttons ourselves in the application.

At the moment we use a custom artwork do draw these, but we are supposed to use artwork from the "Segoe" font-icon [1]

We should use "Segoe Fluent Icons", then "Segoe MDL2 Assets" [2] as a font fallback
We should keep the current behavior on Linux (our custom font) as the Segoe isn't available there.
The related files are CSDWindowButton.qml and CSDWindowButtonSet.qml in modules/gui/qt/widgets/qml

[1] https://learn.microsoft.com/en-us/windows/apps/design/style/segoe-fluent-icons-font

[2] https://learn.microsoft.com/en-us/windows/apps/design/style/segoe-ui-symbol-font

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