* Add horizontal bar at bottom of all non-temp windows, similar to the Top-bar. * Status-bar is hidden in UI-less fullscreen mode * Current contents are preliminary and based on T54861: ** Left: Current file-path if needed. "(Modified)" note if file was changed. ** Center: Scene statistics (like in 2.7 Info Editor). ** Right: Progress-bars and reports * Internally managed as own "STATUSBAR" editor-type (hidden in UI). * Like with the Top-bar, Status-bar data and SDNA writing is disabled. * Most changes in low-level screen/area code are to support layout bounds that differ from window bounds. Design task: T54861 Main changes approved by @brecht.