[Graph RAG] Init Commit with GraphRag interfaces

[randombet]

Why are these changes needed?

Graph RAG is a long-sought feature from the community, we plan to support this and integrate FalkorDB and MS GraphRAG.
Please refer to the design doc for more details.
https://docs.google.com/document/d/15uuNrJrxujX8biPCAZzAtmeMKOFB4SEMkVszcE9nzRo/edit

This is the first PR to set up the graph rag interfaces.

Related issue number

GraphRAG support #3119

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/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.

[thinkall]

Thank you @randombet for the PR. I've left some minor suggestions.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 33 lines in your changes missing coverage. Please review.

Project coverage is 22.24%. Comparing base (6279247) to head (a9c53aa).
Report is 138 commits behind head on main.

Files with missing lines	Patch %	Lines
.../agentchat/contrib/graph_rag/graph_query_engine.py	0.00%	14 Missing ⚠️
autogen/agentchat/contrib/graph_rag/document.py	0.00%	12 Missing ⚠️
...gentchat/contrib/graph_rag/graph_rag_capability.py	0.00%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3388       +/-   ##
===========================================
- Coverage   32.90%   22.24%   -10.67%     
===========================================
  Files          94      105       +11     
  Lines       10235    11095      +860     
  Branches     2193     2540      +347     
===========================================
- Hits         3368     2468      -900     
- Misses       6580     8383     +1803     
+ Partials      287      244       -43     

Flag	Coverage Δ
unittest	11.90% <0.00%> (?)
unittests	22.18% <0.00%> (-10.73%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[gagb]

Is it correct that this PR creates the interfaces for GraphRAG but does not fully implement it? Will example notebooks and use cases be added to this PR?

[thinkall]

Is it correct that this PR creates the interfaces for GraphRAG but does not fully implement it? Will example notebooks and use cases be added to this PR?

The original plan is to first add interface and then add implementations. In this PR, only interface will be added. WDYT? @gagb

[gagb]

Thank you @thinkall I trust your expertise on this PR! Is there a reason to merge this before adding an implementation? Also can we remove the changes in the notebook -- they seems to be unrelated :) But the changes in the notebook are also non consequential.

[randombet]

@thinkall I updated the PR, pls review.
I checked FalkorDB, MS GraphRAG, LlamaIndex with NebulaGraph.
The change to use capability is because

1. Current Graph RAG implementation frameworks integrate retrieve and generate together.
2. Graph RAG Framework retrieve module assumes they knows about the underling graph hierarchy that we could not separate from Agent side.
3. This is also easier for us to integrate to agent.

[thinkall]

Thank you @randombet , would you like to add a test for graph_rag? Thanks.

[gkorland]

Thanks! When do you plan to release the next version with this capability?