Use album artists in ncmpcpp library

.ncmpcpp/config

@@ -67,3 +67,6 @@ visualizer_color = "magenta"
 search_engine_display_mode = "columns" (classic/columns)
 follow_now_playing_lyrics = "no"
 clock_display_seconds = "yes"
+
+# Use album artist in library
+media_library_primary_tag = album_artist