Integrate ORS as online routing provider in popular mobile navigation apps

Many OSM-based mobile navigation apps allow choosing from a variety of online routing providers. Integrating the OpenRouteService within some of these apps would highly increase exposure to users while not increasing server load too much.
Integration in [OsmAnd](https://github.com/osmandapp/Osmand) could be a good start since it is open source and open for pull requests.

Start by reviewing the OpenRouteService issue and the OsmAnd repository to understand how an online routing provider could be integrated. Define the required provider integration and confirm that it works in OsmAnd; the issue provides no specific files or tests to guide implementation.

Written by the indexing model from the issue text.