New, cleaner, coroutine-based client implementation

[MrApplejuice]

Started work on a new babybuddy-api client leveraging retrofit and jackson for automated data binding!

The new client uses generics-based query functions to directly query data types via the client in coroutine functions. This makes it a lot easier to configure and support new data bindings for which, up until now, I had to hand-spin the serializers and deserializers.

A huge milestone that will be reached after this is done, is that the timeline will support showing all current events and measurements/what-have-you that are supported in baby buddy. Not editing, just showing!

Current state

• All events/activities are bound
• Refactoring the old ChildEventHistoryLoader to use the new v2client
  • Broken! History does not auto-update right now
  • Broken! Exception handling for getEntries. Reveals a deeper problem: How to implement exponential backoff and the "spinning waiter" now?
• TimelineObserver can be removed!
• *Broken! Not filtering events by child - all events are shown now (lol!)
• Fix slight bug where observers are not cleaned up correctly after booting the app and switching from child=1 to child=2 for example. After the initial load, everything works fine though. Probably related to the ViewPager-life cycle.
  • Cannot reproduce...
• Check lifetime of queued coroutine calls!
• Add new API-backend calls to DEBUG-interface