Update Camouflage Mocks to Support gRPC

[mdemoret-nv]

This PR adds mocks to Camouflage to support mocking the Triton gRPC endpoint. Currently its a pain to set up testing because we much use MagicMock for mocking Triton with Python and Camouflage when mocking with C++. This would unify them to both use Camouflage.

Some outstanding issues:

• This requires setting the request id field. Are we sure this wont have any side effects?
• What is a good way to update these payload files if they change in the future?
• What organization should we use for the payload files. Its not as clear as the HTTP folder structure
• Can we use the same payload for both HTTP and gRPC?
• The request ID solution is a bit hacky for HTTP requiring some weird tricks. Are we ok with that?

[dagardner-nv]

This requires setting the request id field. Are we sure this wont have any side effects?
I think in this case it works as it is something built-in to the Triton client/server, and offers the ability to perform some sanity checks on the responses. This does mean we could make the launch_mock_triton a session scoped fixture and only need to launch it once.