Get rid of manually created IKeystoreService.

Java/aidl side changes necessary to generate IKeystoreService.cpp
Generated C++ service currently doesn't support null parameters, so lots
of parameters were updated to pass default value instead of null.

Test: cts-tradefed run cts -m CtsKeystoreTestCases
Bug: 68389643

Change-Id: Ifaf2ab48b2bcd7b081e4b336aa279fa8ba4fbbbf