[DeviceAwareAppOp] Add device attributed AppOp accesses to the recent access file

This CL contains following changes:
1) Create a new AppOpsRecentAccessPersistence class to manage read/write of AppOp recent access file.
2) Instead of calling getPackagesForOps() to get all op accesses from the memory, use AppOpsService.mUidStates. This is to make it easy to get AppOp accesses from all devices by reading the raw data from mUidStates.
3) Add "dv" as a new XML attribute on the attributed op tag to represent an access entry from an external device. Add "pdv" as a new XML attribute to indicate the proxy is on an external device.

Bug: 336802155
Test: Added a new unit test for persistence: atest AppOpsRecentAccessPersistenceTest
Change-Id: I9a781f7de19dc0fc30de1f1335e21cf724ed2c88