Split emulator into 2 artifacts

[igorbernstein2]

This was motivated by #1234

Currently the emulator artifact serves 2 purposes:

1. it packages the golang binaries and wraps it a java process controller
2. Provides grpc helpers to build a ManagedChannel to the emulator

These 2 purposes are currently handled by making grpc-api a provided api. This should be cleaned up by pulling out the zero dependency binary wrapper and process controller into a separate artifact and change the current artifact to have a hard dependency on grpc and the new artifact.