[Feature] Background Music

**Packages**

Media

**Describe the solution you'd like**

Before and after meetings it's customary to play kingdom melodies at a low volume. This can be done on jw.org but it would be good to provide built in functionality to do this. The Songs tab would be a good place.

**Describe alternatives you've considered**

Playing from jw.org

**Additional context**

N/A

Start by reviewing the Media package and the existing Songs functionality referenced in the issue. Determine how background music would fit the API and Songs tab, including playback behavior and available content; the issue does not name files, tests, or a completion criterion.

Written by the indexing model from the issue text.