Add new IRemotelyProvisionedKeyPool service to keystore2

This service allows clients to request remotely provisioned attestation
keys. These blobs are only usable by applications that have the ability
to pass them to a keymint implementation for use as keys.

This API is intended as a short-term solution in Android T to enable
remote key provisioning for identity credential keys. In Android U,
the underlying service will be updated to be more flexible allowing for
IRemotelyProvisionedComponent to be implemented by things other than
keymint.

Test: keystore2_test
Test: RemoteProvisionerUnitTests
Test: VtsHalRemotelyProvisionedComponentTargetTest
Bug: 194696876
Change-Id: I5ddb1bd087b606ccea88ccf170b99d5bc1b4501d
6 files changed