Expose a new public column network_type_bitmask and deprecate

bearer_bitmask gradually.

Add a new attribute networkTypeBitmask in ApnSetting, and it will be set as 0 if
networkTypeBitmask is not provided in the constructor.
ApnSetting.networkTypeBitmask will be mapped to DataProfile.bearerBitmap in
DcTracker.createDataProfile if existed.

Bug: 21276001
Test: Basic telephony sanity
Change-Id: I58964aab074ca3402066e31c28102401f239a083