TwilightService v2.0

- Switched to using CalendarAstronomer for more accurate sunrise/sunset
  times.
- Exposed sunrise/sunset times via TwilightState so that clients can
  track the current twilight period and perform their own
  interpolations.
- Adopted LocationRequest API for fused location updates:
  (low power, min 1h, max 10m).
- TwilightService is now only activated when a listener is registered,
  minimizing impact to system health on platforms / configurations
  where twilight state is not needed.

Bug: 28588307
Bug: 30190450
Bug: 30282370
Bug: 30650316
Change-Id: Ic5c94d8608e8bb3a3d895e623676a1468d4abdcd