Merge "[KV] Move KVBT to its own package"

services/art-profile

.../java/com/android/server/backup/BackupManagerService.java

...ava/com/android/server/backup/internal/BackupHandler.java

.../java/com/android/server/backup/internal/BackupState.java

...ava/com/android/server/backup/keyvalue/BackupRequest.java

...om/android/server/backup/keyvalue/KeyValueBackupTask.java

...c/com/android/server/backup/BackupManagerServiceTest.java

...ndroid/server/backup/keyvalue/KeyValueBackupTaskTest.java

...roid/server/testing/shadows/ShadowKeyValueBackupTask.java