Add simActivationState to PhoneStateListener

- new public SimActivationState
- hook with PhoneStateListener, notifying registrants when voice&data
  activation state changed

Bug: 31061369
Test: existing TC runtest --path frameworks/opt/telephony/tests/telephonytests
Test: new TC runtest --path
frameworks/opt/telephony/tests/telephonytests/src/com/android/internal/telephony/SimActivationTrackerTest.java

Change-Id: Ieefe2698fe6055a980d225f5ce74f52aef0daab4