Implement new Go based Desktop app

This focuses on Windows first, but coudl be used for Mac
and possibly linux in the future.

app/tray/tray.go

@@ -0,0 +1,33 @@
+package tray
+
+import (
+	"fmt"
+	"runtime"
+
+	"github.com/jmorganca/ollama/app/assets"
+	"github.com/jmorganca/ollama/app/tray/commontray"
+)
+
+func NewTray() (commontray.OllamaTray, error) {
+	extension := ".png"
+	if runtime.GOOS == "windows" {
+		extension = ".ico"
+	}
+	iconName := commontray.UpdateIconName + extension
+	updateIcon, err := assets.GetIcon(iconName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load icon %s: %w", iconName, err)
+	}
+	iconName = commontray.IconName + extension
+	icon, err := assets.GetIcon(iconName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load icon %s: %w", iconName, err)
+	}
+
+	tray, err := InitPlatformTray(icon, updateIcon)
+	if err != nil {
+		return nil, err
+	}
+
+	return tray, nil
+}