Clean up QPalette handling in DecorationPalette
When using a "legacy" colorscheme, the QPalette will be loaded twice. With this change, the QPalette is going to be created only once. It also cleans up variable naming.
When using a "legacy" colorscheme, the QPalette will be loaded twice. With this change, the QPalette is going to be created only once. It also cleans up variable naming.