Release 2.5.0

Changes

Added new call listStationsWithAdvancedSearch for creating more complex queries to the API.
Added Station geoLatitude and geoLongitude.
Added the getServerStats call.
Fix: Mapping of now necessary CountryCode was broken.
Fix: Deprecation of the RadioBrowser.DEFAULT_API_URL and the related constructor. The cluster concept of radiobrowser is to rely on DNS roundrobin and probing. The German RadioBrowser.DEFAULT_API_URL returned HTTP 503 today which sucks.
Fix: "Improvable stations" are gone in the REST API, they are now deprecated and return empty lists/streams.
Fix: resolveStreamUrl used old broken REST API endpoint, moved to new one.
Refactored code to use a common ParameterProvider for mapping parameters to Maps.
Re-created offline wiremock tests
Integration test or real-world tests with real radiobrowser API