Remove duplicated helper functions, move them to utils package

utils/files.go

@@ -0,0 +1,17 @@
+package utils
+
+import (
+	"mime"
+	"path/filepath"
+	"strings"
+)
+
+func IsAudioFile(filePath string) bool {
+	extension := filepath.Ext(filePath)
+	return strings.HasPrefix(mime.TypeByExtension(extension), "audio/")
+}
+
+func IsImageFile(filePath string) bool {
+	extension := filepath.Ext(filePath)
+	return strings.HasPrefix(mime.TypeByExtension(extension), "image/")
+}