Add a Telephony Debug Surface
This commit adds a small surface to allow telephony
to generate events for an external logger to capture
and use to take action such as gathering bugreports
or proprietary logs.
The event-IDs are considered non-stable, so they may
change from release to release or device to device.
Bug:
120941729
Test: manually tested by modifying Settings. Further
tests will require the creation of a package
that has READ_PRIVILEGED_PHONE_STATE.
Change-Id: I6360dab2d997d518ebd5f38a72fe88801e693bb7