FIR-12: orchestrator per namespace

[shorsher]

So far in the implementation of FIR-12, we have tried to avoid creating multiple instances of managers/plugins/etc. unless absolutely required. After some discussion with @peterbroadhurst, @awrichar and I are going to investigate introducing a orchestrator per namespace. The main catalyst for this change is HA firefly.

What the world would potentially look like:

• One orchestrator per namespace
• NamespaceManager handles parsing config and instantiating orchestrators
• A global function to get orchestrators by namespace
• Each orchestrator contains:
  • Singletons for each manager (broadcast, assets, batch, etc.)
  • The configured plugins for the orchestrator's namespace

[awrichar]

#855