Create NN AIDL adapter

This change adds the following adapters:
* nn::IDevice -> BnDevice
* nn::IPreparedModel -> BnPreparedModel
* nn::IBurst -> BnBurst
* nn::IBuffer -> BnBuffer

Bug: N/A
Test: mma
Test: locally created a binderized service with this adapter code,
      which passed VtsHalNeuralnetworksTargetTest
Change-Id: I966f65a1e4d75284c050b77f3f40c515e4970130