* Move gatekeeper aidl definition to system/core/gatekeeperd
* Retire hand written IGateKeeperService and use generated instead
* Adjust gatekeeperd to use the generated aidl stubs.
* Annotated enroll parameters with @nullable to match the
documentation and the way it was used. (The hand written
code was tolerant to null parameters, but it was undefined behavior.)
* Removed Software implementation from gatekeeperd.
* Also removed the upgrade path.
* Software implementation including test moved to
hardware/interfaces/gatekeeper/1.0/software
Change-Id: I72b734db6f67b79b29c2629764490d75d179908a
Merged-In: I72b734db6f67b79b29c2629764490d75d179908a
Test: Manually tested setting pin and login.
