Migrate the MVP into kotaemon (#108)

- Migrate the MVP into kotaemon.
- Preliminary include the pipeline within chatbot interface.
- Organize MVP as an application.

Todo:

- Add an info panel to view the planning of agents -> Fix streaming agents' output.

Resolve: #60
Resolve: #61 
Resolve: #62

knowledgehub/agents/rewoo/agent.py

@@ -269,4 +269,5 @@ class RewooAgent(BaseAgent):
             total_tokens=total_token,
             total_cost=total_cost,
             citation=citation,
+            metadata={"citation": citation},
         )