Implement API to store and retrieve recovery status.

Currently recovery agents can set/get statuses only for  their own keys.

Bug: 66499222
Test: adb shell am instrument -w -e package \
com.android.server.locksettings.recoverablekeystore \
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I5cb70ce139ca29c066d46d0bd4d2967bd3c30843