keystore2 support for app UID migration

- Update migrate_key_namespace to accept specific UIDs for APP domain
  source and destination key descriptors
- Add new API to maintenance service to query a list of aliases for
  specified app UIDs

Test: atest SharedUserMigrationTest#testDataMigration (in internal)
Bug: 211665859
Change-Id: Ica06a8cd7c3f7b85f58d5953a22231cf7e9a1d7f
4 files changed