Export lib3 to AOSP (external/libtextclassifier part)

1. Include both annotator (existing one) and actions(new one for smart
   reply and actions)
2. One more model file. actions_suggestions.model is dropped to
  /etc/textclassifier./ It is around 7.5mb for now, we will slim down
  it later.
3. The Java counterpart of the JNI is now moved from frameworks/base
   to here.

Test: atest android.view.textclassifier.TextClassificationManagerTest

Change-Id: Icb2458967ef51efa2952b3eaddefbf1f7b359930