Enable file encryption on /data partition

For now, the default implementation will be used. In the future,
microdroid-specific keymint HAL will be implemented.

Bug: 185767624
Test: atest MicrodroidHostTestCases
Test: mount userdata.img and see files encrypted
Change-Id: I593e659b60d6b33b153f8d614395755e83e597de
2 files changed