Added configurable priority on apn types

Made priorities configurable through carrier config.

Test: atest com.android.internal.telephony.dataconnection
Test: atest com.android.internal.telephony.PhoneSwitcherTest
Test: Make phone call
Test: Send text message
Test: Hit websites on chrome
Test: Use carrier config local_override broadcast and view logs
Bug: 152324921
Change-Id: I9c8e8d1f1bd3111206719fe6c4f9302e3b1e3d89