Main changes:
● Enabled experimental compilation of Kvantum's plugin against Qt6 (see INSTALL.md). It will be the default when Qt6 becomes the default version of Qt in well-known distros.
● Added a workaround for KWin-Wayland's menus and tooltips (they are polished before the platform is set to wayland).
● Added a workaround for missing panels and frames of LibreOffice's input fields.
● Added an option (to Kvantum Manager) for not blurring inactive windows.
● Added a safeguard when dragging windows from buttons (which became possible in previous versions).
● Removed the workaround for the fixed Qt5 bug QTBUG-47043 but added another workaround for a similar bug in Qt6.