Suggestion: Add Minimize method to FullScreenPresenter

[benstevens48]

Currently there is no way to directly minimize a fullscreen window (without using Win32 APIs). One has to change to an OverlappedPresenter first, but then when the window is restored it is no longer fullscreen. It ought to be possible to minimize the window directly. I suggest the Minimize() and Minimize(bool activateWindow) methods should be copied from OverlappedPresenter to FullScreenPresenter (and probably to CompactOverlayPresenter as well although I haven't used that).

As an example of an app that implements this behavior, see the built-in Photos app.

The workaround code is not difficult (see below), but it would be good to avoid having to use Dll imports.

        public static bool MinimizeWindow(Window window, bool activate = false) {
            if (window == null) {
                return false;
            }
            var hwnd = WinRT.Interop.WindowNative.GetWindowHandle(window);
            return ShowWindow(hwnd, activate ? SW_SHOWMINIMIZED : SW_SHOWMINNOACTIVE);
        }

        /* Win32 imports */

        private const int SW_SHOWMINIMIZED = 2;
        private const int SW_SHOWMINNOACTIVE = 7;
        [LibraryImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.I4)]
        private static partial bool ShowWindow(IntPtr hwnd, int nCmdShow);

        /* */