Remove the wear module

[caarmen]

With Android Wear 2, the notification doesn't display as nicely as it did on Android Wear 1.

So, we take the opportunity to simplify things.

• No more google play services
• No more need for a wearable module, or for a common module.
• No more proprietary vs foss flavors: just the default flavor now
• One setting for a system notification
  • the system notification is no longer "local only": it will appear on wear devices
  • we can set the background color for the system notification, but that's about the only wear customization we can do, not requiring google play services