[DO NOT MERGE] Handle cell broadcasts with new module

This is gated by a flag sEnableCbModule. Also add logic to trigger cell
broadcast with an intent, gated with the flag TEST_MODE. The framework
interfaces with the module through CellBroadcastServiceManager, which
manages a single binding for all phones in mSIM cases.

Also add a dump(), which can be triggered with `adb shell dumpsys isms`

Bug: 135956699
Test: manual
Change-Id: Ica6e285c4ed73df3c665595808bfeaf2107d96dc