Add more digests to AndroidKeyStore API.

This adds MD5, SHA-1, SHA-224, SHA-384, and SHA-512. SHA-256 was
already there.

MD5 is not exposed for HMAC on purpose, because MD5 has been
deprecated for years.

Bug: 18088752
Change-Id: I4df3d3f6cf10805c7910a1bdb577a91c85055945