App: Turn instructions on waypoints

[devemux86]

@rumbrummer

My proposal (perhaps to complex, as a discussion base)

In fact it is quite simple and also my thinking.

@rumbrummer

use Waypoint symbol (flag) for via points

Any turn instruction with a direction must have the direction symbol.
We can enrich via instruction to [Waypoint name + Turn instruction].

Each routing service can have different behavior:
BRouter, GraphHopper + Kurviger, OpenRouteService, OSRM, etc.

BRouter does not generate (double) turn instructions on via and shaping points.
We can only have the [Waypoint name] instructions on waypoints with BRouter.

BRouter did not generate either the [Waypoint name] instructions on waypoints.
I generate them myself when I post process BRouter routing:

App: Improve BRouter turn instructions

BRouter does not generate turn instructions for waypoints. So BRouter routes don’t know waypoints, only start + end. That may concern navigation (reported here and here). We must post process & enrich BRouter results before use. Related to the feature: https://forum.kurviger.com/t/app-offline-routing-brouter/649