Clean up facade naming and paths

Remove "cert" from build rules that apply to stack under test

hal/facade/* -> hal/
api.proto -> facade.proto

In proto -> [x]Facade
Module -> [x]FacadeModule
Grpc service -> [x]FacadeService

A few straggling references to HciCmd and HciEvt

Test: atest --host bluetooth_test_gd and ./cert/run_cert.sh

Change-Id: I471a49f65a216d6669b3cb7f5ffebc7c069e2d6d