Convert Gatekeeper from HIDL to AIDL

Replaced HIDL spec implementation with AIDL spec in gatekeeper
module. Based on the changes in aosp/2161796.

Bug: 268342724
Test: VtsHalGatekeeperTargetTest, CtsVerifier
Change-Id: Ic322e5c5a7d0577df28410a546cbad88549158bc
8 files changed