Osu2: setup ProvisionService

ProvisionService will be started when the OSU app is
started with "Provision" command.  This service will
run on a separate thread from the Main thread, to avoid
blocking on the Main thread.  This service doesn't
extend IntentService since it requires to perform
async operations.

Bug: 62388032
Test: am start -n com.android.osu/.MainActivity --es
      "com.android.osu.extra.COMMAND" "Provision"

Change-Id: I32c4eb53830a6b0404af085da98f9533346203eb