Active trucks UI

@MariusVolkhart The commits are kinda goofy since I committed to master by accident and reverted that commit out. This has some mock truck data and shows them on the main screen of the application.
Take a look at how the `VendorTrucksService` class does the networking. This changed in a recent PR. The reason for the change is that doing the network IO asynchronously can lead to a system-wide race condition where updates and sync happen at strange times. This is because the IntentService stops as soon as the method completes.

We can do the async call since an IntentService is already using a worker thread, not the UI thread. Which really also means that starting a new thread for the network call is just overhead.