Add geometries endpoint for trip and pattern in index API

Previously we could get the geometry for a specific trip by using `variantForTrip`, but as it is deprecated, we need something else to get the geometry for a specific trip. As it is missing from the index API, we propose two new endpoints, one for getting the geometry for a specific trip pattern and the second one using the first one providing the geometry for a specific trip (as the pattern is not included in the other APIs). 

They are split into separate geometries for each hop, as we only need the geometries before boarding the vehicle and after alighting it, as they are not provided by the planner API. If the whole line is needed, the polylines can easily be combined after being decoded.