Add LTZP status APIs to the SDK

Give TimeZoneProviderService implementations the ability to supply
(optional) status information. This status information can be used for
two purposes:
1) To help report status to users in the SettingsUI (once plumbed
   through).
2) To influence higher-level time zone detection behavior, i.e. so that
   the time zone detection can understand that a TZP is unable to
   perform its duties, perhaps something the platform cannot detect for
   itself.

Test: atest core/tests/coretests/src/android/service/timezone/
Test: atest services/tests/servicestests/src/com/android/server/timezonedetector/location/
Bug: 236624675
Change-Id: Ifa66b8c968c0bdf31b6bdf55ead34b3fa1d9e6fa