Add support for iBroadcast as music provider

[robsonke]

This PR adds support for the iBroadcast music service. It's a simple sync of the library with support for albums, tracks, artists and playlists.

iBroadcast is an easy to use, free so you will (or a small fee to support them with some extra features), online music library with your own music. My use case is that I uploaded all of my owned cd's. The cd's are far away in a box but I like to have all music close to me as not all of this is available on providers such as Spotify.

If you allow this in, I can PR a documentation page too. Just let me know.

More info here: https://ibroadcast.com/home/
And some FAQ: https://www.ibroadcast.com/faq/

[OzGav]

@robsonke If you want to just give me the text that goes in the four sections of the music provider page I can do it up for you. Simple example is this one https://music-assistant.io/music-providers/siriusxm/

I have started making some changes in preparation for this....

[robsonke]

I will try to provide you that later today, anyways asap.

[robsonke]

The plain markdown, it's not a lot of info but all should work straight away:

!!! note
    - Both the free and paid subscription are supported. 
    
## Features

- Basic sync of your iBroadcast library
- Support for Artists, Albums, Tracks and Playlists

## Configuration

User your account username and password to authenticate. This will automatically start importing your full library.

## Known Issues / Notes

- The initial sync can take some time in case of a large library. The API of iBroadcast is not so refined, so it downloads all content at once.

## Not Yet Supported

- Folders and tags

[OzGav]

Perfect thanks!

[marcelveldt]

It's a simple sync of the library

Just add a small note to the docs what the intention is and expectations can be for a user and its all fine

[marcelveldt]

Nice work!