Windows tray menus (#2181)

* Add example

* Add windows systray

* Add gitkeep

* use windows.GUID

v2/pkg/options/systemtray.go

@@ -0,0 +1,26 @@
+package options
+
+import (
+	"github.com/wailsapp/wails/v2/pkg/menu"
+)
+
+// SystemTray contains options for the system tray
+type SystemTray struct {
+	LightModeIcon      *SystemTrayIcon
+	DarkModeIcon       *SystemTrayIcon
+	Title              string
+	Tooltip            string
+	StartHidden        bool
+	Menu               *menu.Menu
+	OnLeftClick        func()
+	OnRightClick       func()
+	OnLeftDoubleClick  func()
+	OnRightDoubleClick func()
+	OnMenuClose        func()
+	OnMenuOpen         func()
+}
+
+// SystemTrayIcon represents a system tray icon
+type SystemTrayIcon struct {
+	Data []byte
+}