Load and generate key from keystore in reboot escrow

According to the design, we need to wrap both reboot escrow key
and reboot escrow data with an additional key from android
keystore. The new key in keystore is created upon a new resume on
reboot request, and cleared after decryption is attempted at boot
time.

Bug: 172780686
Test: atest FrameworksServicesTests:RebootEscrowDataTest \
            FrameworksServicesTests:LockSettingsServiceTests \
            FrameworksServicesTests:RecoverySystemServiceTest \
            FrameworksServicesTests:RebootEscrowManagerTests

Change-Id: Ie2b5f559fb5d3217337e31b0dff507b98715384d