This fixes interactions with the window manager including dodging
exclusive zones, correctly sharpening corners when the window manager
sets the maximized mode, and correctly toggling the maximized state when
either F11 or the maximize button are clicked.
A Cosmic application has no way to call `Cosmic<T>::close` to set the
`should_exit` flag there, as far as I'm aware.
So it makes sense to add a `should_exit` method here.
* feat: add support for dark / light mode switching and simultaneouscustom light / dark mode themes
* refactor(color-picker): optional initial color and fallback color
* refactor: used FixedPortion for layout of the settings item
This makes sure that the control always has at least the specified portion of the available space
* refactor: make all members of the ThemeBuilder public
* refactor: add and update palette colors
* fix(theme): typo and derive PartialEq for ThemeBuilder
* fix: update color picker usage
* feat: add more variables to the theme
* fix: radius on headerbar
* fix: Theme CosmicConfigEntry impl
* chore: specify rev of taffy
* fix: theme CosmicConfigEntry missing variables
* fix: apply theme type when theme mode changes
* wip: add plus icon to empty color picker button
* chore: fix rev and imports
* refactor(color-picker): allow custom size for the icon
* refactor(color_picker): make color_button public
* update iced
