feat: pass selfhosted embeddings to graphrag

[mkhludnev]

Description

• Just a demo how to pass self-hosted openai embeddings via admin settings to graphrag search
• not yet fixes How to set the graphRAG with local ollama #212

Type of change

• New features (non-breaking change).
• Bug fix (non-breaking change).
• Breaking change (fix or feature that would cause existing functionality not to work as expected).

Checklist

• I have performed a self-review of my code.
• I have added thorough tests if it is a core feature.
• There is a reference to the original bug report and related work.
• I have commented on my code, particularly in hard-to-understand areas.
• The feature is well documented.

[taprosoft]

This only works for retrieval time but not indexing time. Temporary close for now.

[mkhludnev]

This only works for retrieval time but not indexing time. Temporary close for now.

ah right. I configured graphrag manually.