Add (disabled) time zone update system server impl

This commit builds on top of prior API commits. It
adds code to the system server, but in a disabled way.

The system server is responsible for monitoring two
(configured) package names: one for the "updater app"
(provided by the platform) and one for the "data app"
(provided by the OEM). When either package changes
the updater app is triggered via a privileged
intent.

The updater is then required to communicate with the
data app and report back to the system server.

Unit tests are included for the major components.

To run:
make -j30 FrameworksServicesTests
adb install -r -g "out/target/product/angler/data/app/FrameworksServicesTests/FrameworksServicesTests.apk"
adb shell am instrument -e package com.android.server.timezone -w com.android.frameworks.servicestests \
    "com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner"

Test: See above.
Bug: 31008728
Change-Id: I8f82cdcc2b574778a7e0d0184270f305b69ee17b