Implement multi-SIM capabilities (1/6) [DO NOT MERGE]

- Split PhoneAccount into PhoneAccount & PhoneAccountMetadata
- Move PhoneAccount methods from TelephonyManager to TelecommManager

Bug:16292368
Change-Id: Ib440368d6bd0572b63c942360450fde5c27d84b9
(cherry picked from commit 936b3552b4a3569be9904c826b95b632886fb45d)
9 files changed