Download bounce + menu

1. Full screen mode for file previews in Tauri Full screen is problematic as Tauri does not support `element.requestFullscreen()`. Now js can request window fullscreen mode, but there is still need to fullsize the media object. 2. Make Download folder bounce when download is done Created crate for Objective C helperfunctions. Dockbounce is automatically triggered when download is finished in the Rust part using `notifications::make_download_bounce(download_path.to_string_lossy().as_ref());`. 3. Menu bar for macOS (Settings + Profile buttons, Check for Updates et al) Menu bar working, click events get passed to JS and can be handled in `UtilitiesRuntime` listening on the `tauri://menu-event`. 4. About [Prose.app](https://prose.app/) window for macOS (fill it with Prose website and details) This could be passed to the js frontend then a custom about page could be built in HTML.