Add security class keystore2_key.

Keystore 2.0 has a different set of permission that it enforces.
We introduce keystore2_key so that we can set up policy for both
Keystore 1.0 and Keystore 2.0 for a gradual transition from one to
the other.

Bug: 158500146
Test: None
Change-Id: I3dcab06d73d242d63d21883659c304dfab8bf74f
Merged-In: I3dcab06d73d242d63d21883659c304dfab8bf74f
2 files changed