Audio should allow repeat-track mode

### What component of Red (cog, command, API) would you like to see improvements on?

audio

### Describe the enhancement you're suggesting.

Most audio players have two repeat modes: repeat, and repeat-track.

Currently, Red's audio bot has a repeat command that repeats the current playlist.

It would be wonderful if Red also had a repeat-track mode, where the current track is repeated until the user moves the playlist position manually.

**Use Case:** I run online RPG games and we use Red for background ambiance for each scene. Ideally I would be able to make a playlist for the game, set to repeat-track, and then manually move the playlist position for each scene. Currently my work around is to make playlists with 1 track each, but that is more difficult to manage while playing.

### Anything else?

_No response_