Feature: A small integrated audio player - possibly inspired by RockBox.

[sandreas]

used Hardware:

• TWatch 2020 or TWatch 2021
• M5Paper
• M5Core2
• WT32-SC01

Is your feature request related to a problem? Please describe.
I am looking for an iPod Nano 7 replacement, so it would be cool to have a little audio player integrated.

Describe the solution you'd like
I would love to see a little app for playing audio from the SD card at least. I think this projects would be very helpful with that:
https://github.com/schreibfaul1/ESP32-audioI2S
https://github.com/schreibfaul1/ESP32-MiniWebRadio

Maybe it would also be possible to take parts of the RockBox project (https://www.rockbox.org/) also written in C and very modular, to get started with something as quick as possible.

I'd love to see a simple streaming feature, optionally with first download to sd card as cache, then play. Maybe a sync api with SD card feature would be more battery friendly.

Describe alternatives you've considered
I considered writing my own audio player, but I think it would be an excellent addition to have a bluetooth headset playing audio via smartwatch or wearable.

Additional context
I think it would be best to establish a proof of concept for checking which audio codecs are supported and if there are any problems playing mp3, wav, flac, ogg or m4a... I would really like to see this happen.