Add RecoverableKeyStoreLoader APIs.

Includes parcelables for
1) KeyDerivation
2) User Secret together with its type.
3) Application key entry
4) KeystoreRecoveryData block with all data  necessary to recover
keys later.

Test: none
Bug: 65979689
Change-Id: If59842a92ebbc0e77f95d6a2e5503943e2835062