[GraphRAG] FalkorDB graph rag integration

[AgentGenie]

Why are these changes needed?

This PR integrates FalkorDB. It wraps FalkorDB as a GraphQueryEngine and could be added to an AG2 agent through GraphRagCapability.

I also include a notebook example to show how to use this feature.

Related issue number

part of #68

Checks

• I've included any doc changes needed for https://ag2ai.github.io/ag2/. See https://ag2ai.github.io/ag2/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[marklysze]

Thanks @AgentGenie, updates:

• Text in notebook
• Updated version support of GraphRAG SDK to 0.3.3 - this version has a chat session inbuilt that can keep track of its own query history, so utilising that.
• Default OpenAI model now GPT-4o (as recommended by GraphRAG SDK)
• Tests have been updated to support v0.3.3

In the future I'll add another example. I'm thinking it would be good if we could use the auto-detect ontology capability. Do you think this could be incorporated? Would make it easy for users to load data and query it without having to create a schema/ontology.

[AgentGenie]

@marklysze Two main changes:

1. Use GenerativeModel as arg type and use OpenAI model as default. This would not limit the user to use other LLM models.
2. Update the code that auto generate ontology if not defined by user.

[qingyun-wu]

Approving right now but may need more eyes on this if you can get more reviewers. @AgentGenie please feel free to create an issue to remind us.