Telephony(MSIM): Add support for MultiSim.

--> Subscription specific for Mobile data, roaming and usage
     - Provide database flags as per subscription for both Mobile
       data and Data roaming options.

--> Add sub based API for getAllCellInfo in TelephonyManager.

--> Use Dds subId to get Sim state, roaming state in NetworkPolicyService.

Change-Id: I6ee5d2a22e44fe7d0d68a41af0481ddbbbe21c3f