Enhancement: Allow grouping by album and artist in getSongsB

[andreasm]

Currently the API call getSongsByGenre only allows listing all songs in a genre. For big libraries with perhaps thousands of songs in a genre, this makes genre view less useful.

Could grouping by album and artist be enabled for this API call?

Initially raised on Ultrasonic app GitLab: https://gitlab.com/ultrasonic/ultrasonic/-/issues/1251

Thanks
Andreas