[Feature Request] Subsonic API suppprt

### Is your feature request related to a problem? Please describe.

Jmusicbot currently doesnt have Subsonic API support.

### What is your ideal solution to the problem?

Include support for Subsonic API.

### How would this feature be used?

1. Ability to play music/playlists/podcasts from a subsonic API supported/forked music streaming servers like Subsonic, Libresonic, Airsonic, Navidrome etc.

### Additional Info

_No response_

### Checklist

- [X] I have checked [the documentation](https://jmusicbot.com/) to make sure this feature doesn't already exist
- [X] I have searched for [similar feature requests](https://github.com/jagrosh/MusicBot/labels/enhancement)
- [X] I have confirmed that my requests is **not** on the [list of things that will not be added](https://jmusicbot.com/things-that-wont-be-added)
- [X] I am running the latest version of the bot: 

The issue names no files, entry points, or tests. Start by reading the Java music-source and playlist integration points, then determine how Subsonic-compatible servers such as Airsonic and Navidrome should be supported. Done would require agreed playback, playlist, and podcast behavior plus tests for the integration.

Written by the indexing model from the issue text.