This implementation follows the reference from soundcork pull request #158. It adds RADIO_BROWSER to the known providers and includes the service configuration in bmx_services.json. Documentation has also been added to explain how to use the RadioBrowser feature. Credits to @gmuth (https://github.com/gmuth) for the original idea and implementation in soundcork. Reference: https://github.com/deborahgu/soundcork/pull/158
