Create fetchRoute() method within FirebaseViewModel

[VigneshSK17]

@DattaKansal Added the changes to MapManager and NomadRoute for storing and fetching routes in Firebase at the branch linked to this issue.

Here the design I had in mind for the storage of the Route in Firebase:

Trip -> TripId -> Route -> RouteId -> { coords: [String] expectedTravelTime: TimeInterval (Encodable) direction: Turf.LocationDistance (Double) }

Storing in Firebase: storeRoute(route: NomadRoute)

• call route.getRouteInfoMap() to get the route information as shown above (coords, expectedTravelTime, direction)

Fetching from Firebase: fetchRoute(routeId: UUID, mapManager: MapManager)

• once you get the route info data from firebase, use mapManager.dataToNomadRoute() to decode the data into a NomadRoute and return that