Handle "naked" CoverArtIDs (IDs of album, mediafiles and playlists)

utils/slice/slice.go

@@ -1,5 +1,13 @@
 package slice
 
+func Map[T any, R any](t []T, mapFunc func(T) R) []R {
+	r := make([]R, len(t))
+	for i, e := range t {
+		r[i] = mapFunc(e)
+	}
+	return r
+}
+
 func Group[T any, K comparable](s []T, keyFunc func(T) K) map[K][]T {
 	m := map[K][]T{}
 	for _, item := range s {