Pass error responses for Mapbox Directions and MapMatching

[danesfeder]

We are currently checking / passing error responses to Callback#onFailure. From the Retrofit javadoc > Callback#onFailure:

Invoked when a network exception occurred talking to the server or when an unexpected exception occurred creating the request or processing the response.

Technically, when we receive an error code (DirectionsError) from either the Directions or MapMatching API, this scenario is not occurring so we shouldn't force the error message to onFailure wrapped in a Throwable.

[Guardiola31337]

Great work removing the unnecessary wrapper for the "unsuccessful responses" and cleaning up the code / extracting Directions and Map Matching response factories 💪