payload apps: turn into good copy paste fodder / use newest api

example from the top of our head: some of the music apps and LED Painter don't use save utils but have their own reimplementation instead last time we checked.

dunno what else is out there but given that people are likely to take these as examples it would be good to have a look over the bunch of them. happy to go through stuff on our own but we all got different angles/focus points, so the more pitch in the merrier :D!