Tesla has officially added Trip Planning to the Tesla app. You'll be able to plan a trip directly from your phone and then send it directly to your car.
Trip Planning appears to only support a single destination currently, but Tesla will likely expand it to support multiple destination in a similar way to the vehicle's navigation. Trip Planner lets you choose a destination and it'll automatically find recommended charging spots along the route, however, it does not currently support adding your own charging locations.
The feature does have some additional functionality though. It defaults the trip to begin with your vehicle's current charge level and location, however you can edit these values if you plan to start your trip at a different location or with a lower or higher state of charger.
To use Trip Planner, go to the Location section of the Tesla app and tap 'Navigate' at the bottom of the screen.
Tripper Planner appears to be available in most regions.