This patch splits the engine into 3 services, conductor, engine and
health-manager.
The goal here is to make the engine more resilent by isolating the
pieces.
Before this patch each Engine worker could potentially be running many
thousands of threads and multiple thread groups, starving the process.
After this change each process would be limited to a single thread
group of 1000 threads, and more predictable and balanced workloads.
* Added two new services.
* Added workers opt to conductor and health manager.
* Merged Thread Group Manager into Engine Service code.
Change-Id: Id4a27ba934dc9777f7ae5b4d7d0a751318ea7877
54997a14ea