[hwaes] Add hwaes service This is a mock hwaes service, which leverages boringssl to perform AES operations. The mock hwaes service also demonstrates the usage of hwaes lib for server side. Bug: 182963097 Test: com.android.trusty.hwaes.test Change-Id: Ib44efa4fc48ad8af62f2407c140f1cafa9a47f02