Move mobile provisioning APN support into telephony and rework.

This code had to be reworked to cooperate with the new multi-network
logic.  The provisioning flow when using a provisioning APN is:
1. DcTracker detects connecting to provisioning APN, puts up
   notification, and turns off radio (as per b/13190133, b/10328264).
2. User selects notification. ProvisionNotificationBroadcastReceiver
   receives intent, turns on radio, enables fail-fast mode,
   sets up provisioning logic in DcTrackerBase.
3. When radio connects again, DcTracker.completeConnection() launches
   browser to facilitate activation.  Note that activation can be
   performed via any internet connection so it's not a problem that
   browser isn't multi-network aware.

bug:17324098
Change-Id: Ibd1c42b1a75795f90a6483d3d0a5a14f88b193d8