feat(GraphRAG): Support concurrent community summarization

[Appointat]

Description

We batch summarize the graph communities and reduce indexing time by 50%. And now, compared to GraphRAG (Microsoft), GraphRAG (DB-GPT) takes less indexing time (about 80%) and consumes fewer tokens (about 40%) to build a knowledge graph of the same size.

Snapshots:

Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[fanzhidongyzby]

lgtm

[csunny]

LGTM～